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Sediment toxicity and bioaccumulation of toxicants in the zebra mussel, Dreissena polymorpha, at Times Beach, Buffalo, New YorkRoper, Jeannie Marie 30 December 2008 (has links)
This study consisted of a site characterization followed by a biomonitoring study utilizing the zebra mussel, <i>Dreissena polymorpha</i>, at the Times Beach Confined Disposal Facility (CDF), located in Buffalo, New York. Concentrations of the selected contaminants (polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and the following metals: arsenic (As), chromium (Cr), barium (Ba), mercury (Hg), cadmium (Cd), lead (Pb), selenium (Se) and silver (Ag), were at or below detection limits in the water column. In the sediment toxicant concentrations were as high as 549 mg/kg for total PAHs, 9 mg/kg for PCB Aroclor 1248, and 54, 99, 6, 355, 637, and 16 mg/kg for the metals: As, Ba, Cd, Cr, Pb, and Hg respectively. To predict contaminant bioavailability, elutriate and whole sediment toxicity tests were performed utilizing the cladoceran, <i>Daphnia magna</i>. The whole sediment tests showed a significant impact. Control survival was 84%, while the sediment treatment survival range was 1-7%. Mean control reproduction was 86.8 neonates, whereas treatment group reproduction ranged from 1.4 to 9.0. Zebra mussels, placed both in the water column (Upper) and at the sediment level (Lower), survived the 34-day exposure. Contaminants which significantly accumulated in zebra mussel tissue during the exposure period (mg/kg) were total PAHs (6.58), fluoranthene (1.23), pyrene (1.08), chrysene (0.98), benzo(a)anthracene (0.60), PCB Aroclor 1248 (1.64), As (0.97), Cr (2.87), and Ba (7.00). The accumulation of benzo(a)anthracene was statistically higher in the Upper mussels; however, this did not occur for any other toxicant. Accumulation of these contaminants in zebra mussel tissue represent a potential hazard to organisms (ie. fish and birds) which feed on them. / Master of Science
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Zinc distribution in a small stream receiving treated textile wastewaterHay, Jonathan Charles 28 July 2010 (has links)
Effluent samples for a treated textile waste water and treated domestic sewage waste water and water and sediment samples for an 8.2 km region of Ash Camp Creek near Keysville, Virginia, were collected in June, 1977. Effluent and stream water samples were analyzed for various water quality parameters and for suspended, dissolved, and total zinc. Sediment samples were analyzed for zinc and percent loss on ignition. The treated textile waste water was the major source of zinc to the stream. The effluent and stream water samples exhibited a marked partitioning of zinc among the dissolved and suspended fractions of the water column. The ratios of mean dissolved to mean suspended zinc ranged from about 0.76 to about 1.40. The ratios of mean dissolved to total zinc and mean suspended to total zinc ranged from about 0.42 to 0.62 and from about 0.38 to 0.57, respectively. Anomalously high zinc concentrations were found in the sediments 0.80 m downstream from the point of discharge of the treated textile wastewater and appeared to be caused by sedimentation of suspended zinc induced by a reduction in stream velocity. The domestic discharge together with flow from a small unnamed tributary had a moderating effect on the water quality of the stream functioning to dilute stream pollutant load. Sulfide precipitation appeared to be an important mechanism by which zinc was concentrated in the sediments 40 m below the domestic sewage discharge. Zinc concentrations declined further downstream likely as a result of such factors as dilution, sedimentation, and sorption by inorganic sediment particles. / Master of Science
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An evaluation of a modified membrane filter technique for the recovery of fecal coliforms exposed to selected heavy metalsGayle, Benjamin P. 28 July 2010 (has links)
A bench study was conducted to compare two membrane filter techniques for their efficiency in recovering fecal coliforms exposed to selected heavy metals. The effects on recovery by increasing time and metal concentration were also examined.
The recovery methods employed included the standard membrane filter technique (S-MF) and a modified membrane filter technique (M-MF)~ which consisted of a lactose agar overlay and a five-hour preincubation at 35 C. The heavy metals Cd, Cr, Pb, and Zn were examined, each at two concentrations, to evaluate their effect on the recovery of the I. coli test organism, after exposure for 6, 24, and 48 hours.
A statistical analysis of the data found the recoveries obtained by the M-MF to be significantly greater (.0001 level) than those of the S-MF, in all cases. Time was also found to significantly effect recovery, with recoveries decreasing as time increased. A significant difference was also found between the effects of the heavy metals tested and the concentrations of metals was likewise found to significantly effect recovery, with decreased recoveries being obtained at the high concentration of each metal. / Master of Science
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An investigation to determine the rate and degree of recovery of Stroubles Creek after diversion of poorly treated sewage, Blacksburg, VirginiaTaft, Walter D. January 1949 (has links)
M.S.
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Heavy metal concentrations, primary productivity, chlorophyll-a levels, and the autotrophic indices of stream periphyton subjected to wood preservation wasteHeppner, Mary Ellen January 1982 (has links)
A study was undertaken during June through September, 1981, in which the periphyton from ten locations in Culpeper, Virginia, were analyzed for arsenic, chromium, and copper, both upstream and downstream from the source of contamination. The periphyton primary productivity, chlorophyll-a content, and autotrophic index were also determined. Water samples were analyzed for the three metals; arsenic, chromium, and copper.
The highest mean periphyton arsenic and chromium concentration occurred at the station 1.2 miles below the site of contamination. The copper concentration in the periphyton was highest 2.7 miles below the area of contamination. All three periphyton metal concentrations were dependent upon the location of the sampling site, but only the periphyton copper content was dependent upon the date of sampling. All three periphyton metal concentrations below the spill site were higher than normal concentrations found in uncontaminated periphyton.
Periphyton primary productivity was greatest at the station above the spill site and lowest at the site 1.2 miles below the site of contamination. A negative correlation was observed between the productivity and the periphyton chromium concentration. No other relationships were noted. The chlorophyll-a level in the periphyton was dependent only upon the date of sampling, not on the location of the sampling site. No relationships were observed between the chlorophyll-a levels and any of the three metals' concentrations in the periphyton.
The autotrophic indices, the ratio of the organic matter to the periphyton chlorophyll-a concentration, were very high at all stations, indicating organically polluted water. Both the location and date of sampling significantly affected the autrophic index. / Master of Science
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Field- and laboratory-determined behavioral avoidance and gill histological alterations of fish in response to acidic and alkaline pH conditionsWhitaker, James Bernhard January 1982 (has links)
The objective of this study was to evaluate the impact of extreme acidic and alkaline pH excursions of fish populations in streams receiving fly ash settling basin effluent. Fish communities were sampled above and below the effluent outfall in a mountain stream, Adair Run, adjacent to the coal-fired Glen Lyn Power Plant in southwestern Virginia. This effluent, which exhibited a pH increase of up to pH 9.3 as the basin nearly filled, contributed to a downstream decline in species diversity and an increased dominance of the stoneroller (Campostoma anomalum), which displaced more sensitive species.
Laboratory avoidance studies, utilizing a steep-gradient trough apparatus, were used to investigate the potential role of avoidance behavior that may alter fish distributions in acidic and alkaline waters. Stonerollers, rainbow trout (Salmo gairdneri), golden shiners (Notemigonus crysoleucas) and spotfin shiners (Notropis spilopterus) exhibited first significant avoidance responses to continuously decreasing pH conditions at pH 6.0-7.0, well above the 96-hr LC50 values of 4.05 and 4.24 for trout and golden shiners, respectively. When the pH was gradually increased, avoidance thresholds of pH 9.5- 11.0 were observed, beyond the 96-hr LC50 values of 9.13 and 8.86 for trout and golden shiners. Single acute alkaline exposures initially yielded more rapid avoidance responses, with acclimation to alkaline conditions frequently occurring within 30 minutes.
Gill histological alterations, as observed by transmission electron microscopy, were detected following exposure to extreme pH excursions, with more rapid changes occurring with alkaline exposures. Gill tissue showed marked recovery within 8-14 days. / Master of Science
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Comparison of biomonitoring techniques for evaluating effects of jet fuel on bluegill sunfish (Lepomis macrochirus)Doane, Thomas R. January 1984 (has links)
The purpose of this study was to compare the simultaneous effects of the water soluble fraction (WSF) of JP-4, a common military and civilian jet fuel, on survival, ventilatory rate, preference-avoidance behavior, and blood enzymes and ions of the bluegill sunfish (Lepomis rnacrochirus) to determine possible interrelationships and which procedures might be most descriptive of sublethal stress. The dynamic 96-h LCSO for WSF JP-4 was 26.2% (percent of the maximum soluble amount of JP-4). A concentration of 5.1% WSF JP-4 caused a detectable shift in ventilatory functions (rate and amplitude); this concentration was equivalent to the 96-h LCOl. Fish did not display a strong preference-avoidance reaction when exposed to WSF JP-4. Some avoidance occurred at 3.5% and 4.9% WSF JP-4. At concentrations near the 96-h LCSO fish appeared to lose their ability to detect WSF JP-4, indicating potential for fish not to avoid lethal levels of WSF JP-4. Few significant changes in whole and serum blood parameters were measured in fish exposed to 13% WSF JP-4; at near lethal concentrations changes were primarily attributed to osmoregulatory failure. Therefore such changes in blood parameters would not be useful to validate or confirm exposure to WSF JP-4. There were few significant changes in gill and liver histology of fish exposed to WSF JP-4 other than an increase in size or number of lipid vacuoles in the liver of exposed fish. / Ph. D.
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Community responses of aquatic macroinvertebrates to heavy metals in laboratory and outdoor experimental streamsClements, William H. January 1988 (has links)
This research describes aquatic macroinvertebrate community responses to heavy metals (copper, zinc) in experimental streams and at metal-impacted sites in the field. Experiments employed substrate-filled trays which were colonized in the field and then transferred to laboratory or outdoor streams.
Laboratory experiments conducted over three seasons showed that acute (96 h) exposure to copper (Cu) at 15-32 μg Cu/L significantly reduced macroinvertebrate abundance and number of taxa during each season. Owing to differences in sensitivity among taxa, the percent composition of dominant groups varied between control and dosed streams. Mayflies were quite sensitive to Cu, particularly during the summer when water temperatures were higher.
Community responses to Cu and Zn in outdoor experimental streams were similar to those observed at metal-impacted sites in the field. Control streams and field reference Stations were dominated by mayflies and Tanytarsini chironomids. In contrast, treated Streams and impacted field sites were dominated by net-Spinning caddisflies (Hydropsychidae) and Orthocladiini chironomids. The similarity of these experimental results to those observed in the field suggest that macroinvertebrate community responses to heavy metals are highly predictable.
Responses of these communities to Cu were greatly influenced by water quality. Effects were more severe in New River Streams, where water hardness and alkalinity were low, compared to Clinch River Streams, where hardness and alkalinity were higher. In soft water Streams, abundance was reduced by 84% after 10 d exposure to Cu (measured concentration = 13 μg/L). In contrast, abundance was reduced by only 45% in hard water Streams after 10 d at Similar Cu levels. These results demonstrate the importance of accounting for water quality characteristics of receiving systems when establishing site-specific criteria for metals.
Chronic exposure (14 d) to sublethal levels of Cu (< 6 μg/L) increased Vulnerability of caddisflies (Hydropsyche morosa and Chimarra sp.) to predation by the Stonefly, Paragnetina fumosa. Caddisflies were also the major component of stonefly diets and were consumed Significantly more frequently in dosed Streams than controls. These results demonstrate that single Species bioassays were inadequate for predicting effects of toxicants on community level processes. / Ph. D.
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Effects of hexavalent chromium on the growth and reproduction of Chironomus riparius (Diptera)Hax, Carolyn L. January 1983 (has links)
Effects of hexavalent chromium on the life cycle of Chironomus riparius were examined in the laboratory, using sublethal (0.5 mg/1) and 40% lethal (2.0 mg/1) concentrations. Chironomus egg masses were introduced into both control and chromium-treated 21 1 aquaria. Larvae were subsampled at 5-day intervals, measured for length, and weighed to generate growth curves. Emerging adults were allowed to mate and oviposit. Twenty female pupae were collected from control and treatment (0.5 mg/1) populations within 12 hours of pupation. Their bodies were analyzed for lipid content by calculating loss in dry weight after a chloroform-methanol extraction. Chromium body burdens were measured in both larvae and adults from treatment (2.0 mg/1) and control populations. Effects of chromium on hatching rates of egg masses were studied.
Growth was stimulated at both lethal and sublethal concentrations of chromium. Lipid content of female pupae was significantly higher in treatment populations than in controls. Both stimulated growth and increased lipid storage may be the results of metal activation of enzymes involved in energy processing and storage in the insect. Reproductive success, as measured by numbers of offspring per adult female, declined with increasing chromium concentrations. Chromium concentrations in adult males and larvae were significantly greater for treatment populations. Metal body burdens may have become concentrated in eggs or sperm of Chironomus and caused the observed decrease in reproductive success. No direct toxicity of chromium on egg masses was observed at concentrations up to 5 mg/1. / M.S.
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Synergistic adsorption of Pb (II) from aqueous solution using calcined biochar-bentonite clay hybridAbdul-raheem, Azeezat Faderera 13 December 2024 (has links) (PDF)
The biochar-bentonite clay hybrid was prepared by coprecipitation with the goal of producing a material that can remove Pb (II) from aqueous solutions effectively. Incorporating bentonite clay onto the Douglas fir biochar (DFB-BTC) surface significantly improved the adsorption capacity by introducing more active sites, strengthening the structural properties, and promoting strong adsorbate interactions. The point of zero charge of the adsorbent was slightly higher than that of the pristine DFBC. All sorption experiments were performed at pH 5, and the system obeyed the Langmuir adsorption isotherm. The highest Langmuir adsorption capacities observed at 298, 308, and 318 K were 48, 80, and 78 mg/g, respectively, with 99.85% as the highest removal efficiency. The sorption kinetics showed that equilibrium was reached after 2h for both 5 and 50 mg/L Pb(II) solutions, whereas equilibrium was attained after 4h for 100 mg/L, which fit a pseudo-second-order model. The surface characterization was determined using scanning electron microscopy (SEM), X-ray diffraction (XRD), BET, and FTIR. This study aimed to develop a facile, eco-friendly, versatile, low-cost, and hybrid biochar-bentonite clay (BBC) for an exhaustive evaluation of Pb (II) uptake in water.
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