The influence of environmental contaminants on the muskrat population inhabiting the contaminated lower region of the Elizabeth River was studied through an analysis of contaminant burdens, physiological characteristics, and population dynamics in comparison to those of muskrat populations from a less contaminated region of the Elizabeth River (upper region) and a nearby uncontaminated river (Nansemond River). A total of 76 muskrats was collected for contaminant analysis during December 1986 - January 1987 and December 1987 - February 1988. Twenty-two of 35 carcasses analyzed for polynuclear aromatic hydrocarbons (PAHs) had detectable levels of from 1 to 6 PAH compounds. Only three muskrats from the lower region and one from the upper region of the Elizabeth River had PAH concentrations greater than 0.03 ppm dry wt (lower limit of detection). Liver DNA adduct levels were not significantly different between muskrats collected from the lower region of the Elizabeth River and muskrats collected from the Nansemond River. However, liver microsomal enzyme activity was greater in lower region Elizabeth River muskrats than in upper region Elizabeth River or Nansemond River muskrats, as indicated by significantly reduced pentobarbital sleeping times. The mean concentration of 14 PAH compounds detected in surface sediments from the lower region of the Elizabeth River (N = 10) was significantly greater than the mean concentration detected in surface sediments collected from the upper region of the Elizabeth River (N = 5) or Nansemond River (N = 5). Of 22 organochlorine compounds analyzed in 35 muskrat carcasses, dieldrin was detected in one carcass (0.25 ppm) from the lower region of the Elizabeth River, polychlorinated biphenyls were detected in two carcasses (0.66 ppm and 0.45 ppm) from the upper region of the Elizabeth River, and p,p′-DDE was detected in two carcasses (0.03 ppm each) from the upper region of the Elizabeth River and one carcass (0.03 ppm) from the Nansemond River. p,p′-DDE was detected in 5 of 10 sediment samples from the lower region and 2 of 5 sediment samples from the upper region of the Elizabeth River. p,p′-DDD was detected in 3 of 10 sediment samples from the lower region of the Elizabeth River. Twenty-seven of 33 metals analyzed were detected in muskrat kidneys and 9 of these were significantly different among the three study regions. Mean aluminum (13.19 ppm), cadmium (3.08 ppm), copper (12.85 ppm), nickel (0.50 ppm), and zinc (88.38 ppm) concentrations were greatest in lower region Elizabeth River muskrat kidneys. Mean cadmium (1.07 ppm), chromium (43.4 ppm), lead (104 ppm), tungsten (38.1 ppm), and mercury (0.50 ppm) concentrations were significantly greater in lower Elizabeth River sediment samples. Density estimates based on shore length for the lower and upper regions of the Elizabeth River were 0.86 muskrats/IOO m of shore and 1.1 muskrats/lOO m of shore, respectively in 1987. Seventy-five female muskrats had a total of 637 placental scars (x̅ = 8.49) ranging from 1 - 20. The number of placental scars per female did not differ significantly among regions. Twelve pregnant muskrats had a total of 54 fetuses (x̅ = 4.5, range = 3 - 6). Average number of litters per year was estimated to be 1.89 with births occurring primarily from April - May and in September. Results indicated that the environmental contaminants found in the lower region of the Elizabeth River have minimal influence on the muskrats from this region. Body and spleen weights were reduced but reproduction was not affected, and the muskrat density in this region appears to be stable and similar to the density in a less contaminated area. Immunological function may be depressed. / Ph. D.

A stochastic dynamic constituent transport model was developed, capable of simulating the operation of a water distribution system containing pumps and storage tanks, and subject to random demands and contaminant inputs. Long term operation of a hypothetical small town water supply system containing one pump station and one storage tank was simulated while the system was subjected to external contaminant inputs. Repeated simulations were made under different regimes of external contamination applied to the tank, the pump station and at system nodes, and internal contamination representing biofilm effects based on assumed relationships between flow velocities and bioflim cell detachment. Seven sampling plans representing regulatory requirements and industry practice were applied during the simulation to evaluate their ability to detect the contamination under a presence/absence criterion. The simulations were able to identify contamination patterns and provide information useful in the definition of sampling plans. Time of sampling was found to be as important as location. This was true both within the monitoring period, and particularly within the diurnal cycle of demand. Spreading samples over different days within the monitoring period rather than sampling all on one day, always improved contaminant detection. Detection by plans based on fixed times and locations were very sensitive to those times and locations. There was no best plan suitable for all situations tested. The better sampling plans were those that captured the temporal and spatial contamination patterns present in the system. No consistent advantage was noted from sampling in proportion to population served or in locating sampling nodes systematically instead of randomly. The location and timing of sampling for most plans could be improved with the knowledge of actual contamination patterns and timing provided by the model. The presence of a storage tank was found to have a strong influence on hydraulic patterns and the location and timing of contamination reaching different parts of the system. / Ph. D.

The activity of erythrocyte amino levulenic acid dehydratase (ALA-D) and liver and bone lead concentrations were measured in 141 wild rainbow trout from two highway-influenced and two pristine streams. A significant relationship between ALA-D activity and liver lead concentrations among streams (r = 0.157) was observed. However, this relationship was opposite of expected. Trout tissue lead and stream-water lead concentrations were lower than most concentrations observed for control laboratory trout. At these low tissue and water lead concentrations observed in the present study, ALA-D activity cannot be used to document exposure of fish to environmental lead. Other significant correlations with the activity of the enzyme included: trout length (r = -0.411); trout age (r = -0.385); and sediment lead (r = 0.093). Erythrocyte ALA-D activity significantly varied due to sampling period. However, reasons for this deviation cannot be explained from the present study. Multiple regression techniques revealed little concerning trout liver lead concentrations and ALA-D activity relationships. Like ALA-D activity, liver lead concentrations were deemed a poor indicator of organisms' exposure to environmental lead. Bone lead concentrations were the best indicator of environmental contamination. However, the best regression model, which regressed water lead on bone lead, explained only 20.6% of the variation in bone lead burden. In both roadside streams, water lead was positively correlated to turbidity and area precipitation. Water lead concentrations were also positively correlated to discharge in one roadside stream. / M.S.

In this dissertation, the design, implementation, and educational applications of a real-time water and weather monitoring system, developed to enhance water sustainability education and research, are discussed. This unique system, called LabVIEW Enabled Watershed Assessment System (LEWAS), is a real- world extension of various data acquisition modules that were successfully implemented using LabVIEW into a freshman engineering course (Engineering Exploration, ENGE 1024) at Virginia Tech. The outdoor site location measures water quality and quantity data including flow rate, pH, dissolved oxygen, conductivity, and temperature -- as indicators of stream health - for an on-campus impaired stream in real-time. In addition, weather parameters (temperature, barometric pressure, relative humidity and precipitation) are measured at the LEWAS outdoor site. The measured parameters can be accessed by remote users in a real-time through a web-based interface for education and research. LEWAS is solar powered and uses the campus wireless network through a high-gain antenna to transmit data to remote clients in real-time. Its power budget consisting of consumption (14 W), electrical storage, and generation (80 W, peak) is balanced to enable 24/7 operation regardless of weather conditions. An embedded computer with low power consumption and modules for communicating and storing data are installed in the field and it is programmed to process measured environmental parameters to be delivered to remote users. This computer is programmed both using a field programmable gate array (FPGA, for low power consumption and robust operation) and traditional microprocessor programming (for more flexibility). The environmental sensors of the system are routinely calibrated using established procedures. A LEWAS Development Platform was established to develop and test the system and to train and mentor several undergraduate and graduate students who helped in its implementation. A number of design and implementation challenges were overcome including extending campus Internet access to a location not included on the network and integrating hardware and software from three different sensor manufacturers into a unified software platform accessible over the Internet. To study the educational applications of LEWAS, an observational study was conducted as the system was gradually introduced to students in ENGE 1024 between 2009 and 2011. Positive student attitudes on the role of LEWAS to enhance their environmental awareness informed an experimental design implemented to study the motivational outcomes associated with the system. Accordingly, appropriate educational interventions and a hands-on activity on the importance of environmental monitoring were developed for both control and experiment groups, with only the latter given access to LEWAS to retrieve the environmental parameters for the activity. An instrument was developed on the theoretical foundation of the expectancy value theory of motivation and was administered to control and experimental groups in ENGE 1024. Altogether, 150 students participated in the study. Exploratory Factor Analysis (EFA) was applied which resulted in factors that group questions together based on interest, importance, real-time access, and cost (feasibility of monitoring). After conducting parametric and nonparametric statistical analyses, it was determined that there exists a statistically significant difference between control and experimental groups in interest, real-time, and cost factors. This finding implies that providing real-time access to environmental parameters can increase student interest and their perception of feasibility of environmental monitoring -- both major components of motivation to learn about the environment. Future extensions and applications of the system at Virginia Tech and beyond are discussed. / Ph. D.

The purpose of this research was to investigate the relationship between watershed land use and seasonal changes on THM-formation potential from the waters of four streams located in northern Virginia. Specific objectives were to observe the effect of impoundment on downstream THM precursor concentrations and to evaluate the molecular-size distributions of THM-precursors in stream waters as to the influence of seasonal changes, storm events, and watershed land use. Raw water samples were collected from October 1989 through May 1990 during baseflow and storm conditions. The samples were fractionated through 500, 1000, 5000, 10000, and 30000 dalton ultrafilters and were then chlorinated to determine the THM-formation potential based on the total organic concentration of the water fraction. From the data collected, it was shown that seasonal changes influenced the TOC and THM-precursor loadings in runoff from the watersheds. Fall runoff from Broad Run contributed the highest mass loading. Impoundment was seen to increase the amount of THM precursors downstream of Lake Manassas on Broad Run with the largest difference observed during the fall event. The more-rural watersheds draining into Broad Run contributed the most TOC and THM precursors during the fall runoff event, while the more-urban watersheds (Bull Run and Holmes Run) contributed more TOC and THM precursors in the winter and spring runoff. / Master of Science

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

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

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

M.S.

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