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Correlating Residual Antibiotic Contamination in Public Water to
Drug-Resistant Escherichia coli: Is Remediation an Option?
By Ashley Mulroy
Linsly School
Wheeling, WV
Abstract
Purpose: (A) Determine the presence of antibiotics Penicillin, Tetracycline and
Vancomycin along a 44 km stretch of the Ohio River and two tributary streams.
(B) Test in-situ bacteria from each of the test sites for acquired drug resistance.
(C) Determine the viability of selected methods of remediation.
Methods and Materials: (A) Water samples from seven outdoor locations were
collected regularly, over a ten-week period, as well as single samplings of tap
water form each of the three municipalities adjacent to the river. Levels of
antibiotic concentrations in the samples were determined utilizing gel
electrophoresis, resulting in 1050 values of river and stream water data and 135
values of tap water data, upon which standard deviations and confidence levels
were determined. (B) Escherichia coli samples isolated from test sites were
subjected to the Kirby-Bauer Disk Sensitivity procedure to determine the level of
bacterial resistance to Penicillin, Tetracycline and Vancomycin. In all, 28 dish
cultures were studied for sensitivity to the three antibiotics, with measurable data
submitted to a line of the best fit statistical analysis to determine correlation
coefficients. (C) Three PVC fitrate-packed cylinders were utilized to test the
efficacy of mixtures of sterile sand, Saccharomyces cerevisiae culture (Brewer’s
Yeast) and ground activated charcoal as filters for each of the three antibiotics in
question. Standard deviations and confidence levels were determined for the
resulting 135 values.
Observations: (A) All river and tributary sites yielded detectable amounts of the
three test antibiotics in concentrations ranging from 0.7 – 5.9 parts per trillion.
Lesser amounts were detected in tap water. (B) All E. coli samples cultured
from river and tributary sites exhibited acquired antibiotic resistance. Analysis
indicated that the greatest acquired resistance appeared in the samples
containing the highest level of antibiotic contamination. (C) Water samples,
which passed through packed columns of sand (the primary filtrate media used
by municipalities in the mid-Atlantic region of the United States), saw no
reduction in antibiotic contamination. Columns packed with a sand/activated
charcoal mixture removed 93.3% of Vancomycin, 96.0% of Tetracycline and
77.1% of Penicillin concentrations.
Conclusions: The presence of antibiotic contamination in American waterways
results in a progressive resistance among some bacteria to those same
antibiotics that once controlled them. Some remedial filtration techniques have
shown themselves to be effective, but there is further need for both study and
action toward a more responsible utilization of antibiotics if these
pharmaceuticals are to continue to be effective.
Consider quality of life and health in the absence of pharmaceutical
breakthroughs such as Penicillin, Tetracycline and Vancomycin. This research
may serve as a warning that the benefits of antibiotic drugs are gradually being
neutralized, with the bacteria that survive non-lethal exposures to these former
wonder-drugs developing into far more powerful versions of their former
incarnations. A more responsible approach to prescription and utilization of
antibiotics is necessary to enable medical science to maintain control of these
microbial threats to public health.
Photocatalytic
By Hayley Han Li
Bartlesville High School
Bartlesville, OK
Abstract
Purpose: The purpose of this project was to test if the photocatalytic
degradation of N-Nitrosodimethylamine (NDMA) in water on TiO2 was possible.
One liter of 10 parts per million NDMA solution with .2000 grams of TiO2 was
irradiated by a mercury lamp for 18 minutes. This solution was filtered through a
vacuum-driven filtration system so that TiO2 powders would be separated from
the solution. The filtered solution was then tested on the UV visible
spectrophotometer for its light absorbency at 228 nanometers. The absorbency
had lowered from .92405 AU to .32286 AU indicating that the concentration of
NDMA had been reduced. A second test was conducted with 1 liter of NDMA
solution without adding TiO2. This was irradiated for 18 minutes. The
absorbency level was lowered as in the previous experiment, but it occurred
faster. A third experiment wad one with the NDMA solution irradiated for 5
minutes without TiO2. Samples were taken every 30 seconds. The graph of this
reaction showed that NDMA could be degraded by 75% within 5 minutes. The
single isosbestic point on the graph indicated that the mechanism for this
decomposition reaction occurred in one step. The products were predicted to be
dimethylamine and nitrous acid. A comparison of the first and second
experiment suggested that TiO2 did not have a positive influence. One
explanation was that the TiO2 was blocking light that would have been absorbed
by NDMA particles and used in the degradation process. In conclusion, NDMA in
water could be lowered by UV light alone. Since NDMA is a known carcinogen
that is present in various water supplies, the further elimination of it is essential to
the health of humans and other species.
The Design and Development of an In-Line Chitin Filter for
Heavy Metals
By John Paul Rowan
Neil Victor
Geoffrey Loy
Abstract
Chitin, composed of chains of nitrogen containing modified glucose molecules, is
found in the walls of fungi and the exoskeletons of arthropods such as insects
and crustaceans. The crabbing industry in the southeastern United States
annually generates hundreds of tons of chitin containing crab shells which, at this
time, have minimal practical use and end up in landfills. Preliminary studies,
using 50 g samples of boiled, ground crab shells from the Atlantic blue crab,
Callinectes sapidus, indicated that chitin was effective at removing heavy metals
from water. The concentrations of the heavy metals zinc, chromium, copper, and
lead were reduced 97.25%, 98.45%, 86.75%, and 99.45%, respectively (n = 16,
14, 16, and 16 for the individual tests, respectively).
To further test this effect and to find a practical use for crab shells, an in-line,
under the sink filter was designed, tested, and compared with a commercial filter
available on the market today. The filters were filled with 1,100 g samples of
boiled, ground crab shells. The filters were then tested using timers to run a total
of 1200 liters (the limit for the commercial filters) of water contaminated as above
with either zinc, chromium, copper, or lead through them in an intermittent
manner to simulate actual use of a filter used for drinking water. The same was
done with the commercial filter. In all cases, except lead, using atomic
absorption, the levels of the heavy metals exiting our filters were below
detectable limits for the duration of the test. Lead showed a breakthrough at
around 800 liters only removing 97% of the lead for the duration of the test.
These results indicated that chitin is very effective at removing heavy metals from
drinking water and that chitin appears to be as effective as the commercial filter
we tested.
The Incidence and Analysis of Stormwater Runoff in Pittman
Creek
By Dean Tuck
Plano, TX
Abstract
There are thousands of contaminates that have been identified in the rivers and
streams of this nation. Recent studies show that there are too many
contaminants for water treatment plants to handle effectively. What is the
concentration of carcinogenic and toxic organic compounds in Pittman Creek, a
tributary of the Trinity River? This experiment will concentrate on nitrates, total
organic carbons (TOCs), and simazine. Which water treatments will need to be
implemented to make this water potable? Four options will be examined in this
paper.
This third-year project quantifies the impacts of stormwater runoff of Pittman
Creek, which is a tributary of the Trinity River in Texas. The tests conducted
show that all the chemical contaminants: nitrates, total organic carbons, and
simazine exceeded the standards established by the EPA. The Trinity River
supplies a large portion of the water for the Dallas/Ft. Worth area. The quantified
numbers show a river system with chemical contaminants that are not only hard
to extract to make the water potable but also dangerous for human consumption.
The tolerance thresholds for these chemicals have not been established, which
increases the overall health risks. In order to remove the chemicals, major
improvements in water treatment are necessary. To emphasize the improvement
needed, cost impacts for membrane, ozone and granular activated carbon
filtering processes were calculated based on cleaning up the identified chemical
contaminants. Research indicates that membrane treatment is the only water
treatment plant process that will accomplish this. Unfortunately, its
implementation is rare. “Water, water everywhere, but not a drop to drink”.
Water Quality Assessment of an Agriculturally Affected Creek
Compared to a Least Impacted Creek
By Kelly M. Schmeidt
Little Falls Community High School
Fort Ripley, MN
Abstract
The project was designed to compare data of a least impacted creek acting as a
control (Broken Bow) to that of an agriculturally influenced creek (Pike Creek)
and distinguish differences of water quality. Tests performed include pH,
conductivity, dissolved oxygen, nitrate and ammonia nitrogen, phosphorus and
fecal coliform bacteria. Macroinvertebrates were collected and counted.
Bioassays were performed to determine if toxic organics or heavy metals were
present.
The two creeks are nearly equidistant and both empty into the Mississippi River.
Pike Creek has six sites labeled source to mouth, PC1-PC6. Broken Bow has
five sites labeled BB0-BB4. Between 6/24 to 10/17 of 1999, five chemical, two
biological, and one bioassay samples were taken at all sites. Riverwatch
protocol (EPA approval) procedures were used.
Pike Creek showed significant water quality impairment based on the bioassay
testing using Lactuca sativa seed root growth while Broken Bow indicated none,
possibly from toxic organics. Phosphorus levels exceeded ecoregion normal
80% of Pike Creek samples compared with 16% at Broken Bow.
Macroinvertebrate analysis was not sufficient alone to test water quality. The
wetland complex on Pike Creek between PC4-PC5 exhibited filtering effects
dropping conductivity and fecal coliform counts significantly. 60% of Pike Creek
samples compared with 8% of Broken Bow exceeded total body contact
standards for fecal coliform bacteria. Pike Creek has the potential to adversely
affect the Mississippi and is a risk to human health while Broken Bow does not.
Without agricultural impact, Pike Creek’s water quality could be similar to Broken
Bow Creek.
The Effects of High Phosphorus Levels in the Everglades:
Implications for Restoration
By Natalie Elisse Bentolila
Cooper City High School
Cooper City, FL
Abstract
Four locations in Everglades National Park each contain study sites consisting of
four 100-meter-long adjacent channels running north to south, so the natural
water flow can pass through freely. The study sites were studied in their natural
phosphorus level to collect data on ecological characteristics before phosphorus
additions. Periphyton and macrophytes were studied for percent cover area.
Invertebrates and small fish were counted. Water, floc, and soil were studied for
chemical characteristics, enzyme activity, and redox potential. Phosphorus
dosages were then added to each of the channels in different concentrations,
being 0pps, 5ppb, 15ppb, and 30 ppb of phosphorus. A hydrologic regulator at
the head of the channels released the dosages of phosphorus in relationship to
the amount of water flow entering the channels, keeping their phosphorus level
constant. The effects of the phosphorus were observed in periphyton as a
decrease in mat cover area, an increase in algae species changed, and an
increase in macrophyte growth. Invertebrate and small fish count increased and
eventually decreased at higher levels. The effects were observed in water, soil,
floc as a decrease in alkaline phosphatase activity and in system Eh. These
changes were more intense with increasing phosphorus dosages. Results show
the Everglades’ phosphorus intake limit is 5ppb plus ambient, equaling
approximately 10 ppb. The Everglades periphyton and water column is sensitive
to nutrients, and may provide as one of the first indicators of eutrophication in the
marsh. This flume/dosing project is essential to determine how much
phosphorus the Everglade’s ecosystem can handle without causing permanent
damage.
Aquatic Herbicides: Copper Sulfate’s Latent Effect on Primary
Consumers: A Third Year Study
By Cliff Garabedian
Clovis West High School
Clovis, CA
Abstract
This study on trophic consumption and implications for biomagnification is an
extension of earlier work. Previously, the effects of copper sulfate, a widely used
target aquatic herbicide, were investigated at the fundamental level of autotrophic
photosynthetic production. My hypothesis is that copper (Cu) in CuS04, during
herbicide application, may enter the food chains of aquatic systems. To test this
I used field collected crustaceans, Daphnia and Copepods, which are primary
consumers. Copper uptake by the crustaceans was measured by the loss of
copper from a series of prepared CuS04 solutions using filtered pond water
exposed to clean, measured, 1cc amounts of crustaceans. A spectrophotometer
measured copper in mg/L in solutions before and after 16 and 24 hour exposures
to crustaceans. Controls without crustaceans and controls without CuS04 were
prepared along with repeated experimentals and tested for Cu using the
bicinchoninate method. Phase I Daphnia and phase II Copepods revealed a loss
of Cu compared to controls. Daphnia absorbed Cu from .3 mg/L to .9 mg/L per
test volume. Copepods absorbed Cu from 1.5 mg/L to 1.7 mg/L per test volume.
The data suggests potentially toxic Cu enters aquatic ecosystems by
crustaceans and supports my hypothesis. Data analysis rejected the null
hypothesis. Aquatic food chains are more sensitive to bio-magnification because
of the increased density of trophic steps. These findings, along with previous
research, suggest the use of CuS04, an aquatic herbicide, may be associated
with wider than desired biological damage. | |
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