Shane McWilliams
ID #: 975714032
Dr. Richard Parizek, TA: Heather Tollerud
Geosc. 303 Environmental Geology
Fall 2012
November 29, 2012
Composition of Spring Creek
Abstract: Not much is known of the chemical composition of Spring Creek. The main goal of
this research was to go out into the field at select locations along Spring Creek and take
measurements to find out information about the chemical make-up of the creek water. pH,
conductivity, and temperature measurements were taken and used to calculate nitrate and sulfate
concentrations as well as alkalinity. After observing this data, it can be concluded that the
surrounding lithology along with human activity are the primary reasons that pH, conductivity,
temperature, nitrate concentration, sulfate concentration, and alkalinity all increase as Spring
Creek flows downstream to lower elevations.
Introduction: Spring Creek, located in Centre County, PA, is without a doubt the most
significant watershed in Central Pennsylvania spanning across an area of 146 square miles
(PGWA, 2011). The objective of the four labs that were completed is to further familiarize
geologists and the citizens of Central PA with the effects that land use and lithology have on the
composition of Spring Creek. It is important to assess the quality of water in streams because
most of this water flows into bodies of water from which we receive our drinking water and the
water we use in everyday life. If this water is contaminated in any way, it can be a concern to
human health. Also, many plants and animals rely on this water to receive nutrients and if the
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water is harmful, it could potentially cause a widespread killing of wildlife in the area. If this
scenario were to happen, the damages would be devastating, not only to wildlife but it would
directly affect humanity in the sense that our food industry would take a serious hit and disease
could possibly spread throughout the country if nothing was done about it. This may sound a bit
unlikely; however, it is perfectly capable of happening if we don’t keep an eye on the quality of
stream water.
Spring Creek runs from Boalsburg to Milesburg covering many square miles in central
Pennsylvania. Over the course that the creek travels, it goes through different types of
environmental areas including urban areas, farm land, and heavily wooded areas such as forests.
Observations and measurements were taken at eight different locations along the creek including:
Chester County Camp Spring, Galbraith Gap Run, Spring Creek at Boalsburg Military Museum,
Spring Creek Park, Spring Creek at Fisherman’s Paradise, Buffalo Run at Bellefonte, Spring
Creek at Bellefonte, and Spring Creek at Milesburg. Referring to the attached map of the area,
we can see that Spring Creek starts at Chester County Campground and travels downstream to
Milesburg. There are four different types of rock found in diverse areas of the Spring Creek
Watershed with the four types being Shale, Sandstone, Limestone, and Dolomite. The limestone
and dolomite are the most abundant making up the valley floor and the shale and sandstone make
up a smaller quantity at higher elevations. The creek itself runs through a wide array of
elevations where the pH and conductivity differ at various locations along it’s path.
Methods: In order to appropriately observe and evaluate the water of Spring Creek, several
experimental methods had to be used to make measurements and use those measurements to
make calculations that give us an explanation of the water characteristics. Included in the “field
methods” are measurements of pH, conductivity, and temperature. The pH measurement was
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taken using a pH meter which is a device that has a sensor that is submerged into the creek and
digitally gives the pH of the given solution. It was calibrated by testing buffer solutions to
ensure that the instrument was performing accurately. Conductivity was measured with the help
of a conductivity meter which is a small handheld device that is made up of a two metal sensors
on the bottom and a display screen at the top. After submerging the sensors in the water and
waiting a few minutes for the instrument to settle, an accurate conductivity value is given for the
creek. Like the pH meter, the conductivity meter was also calibrated by testing standards. The
conductivity meter also made the temperature measurement.
The “laboratory methods” were made up of finding the absorption values of the samples
and using this value to calculate the concentration of sulfate and nitrate. To test for nitrate, we
first took a sample from Spring Creek and diluted it with pure water until there was a total of 10
mL. A packet of NitraVer 6 Reagent Powder and NitriVer 3 Nitrate Reagent Powder was
eventually added followed by timed periods in which the solution was to be shaken and let sit.
In order to measure sulfate, a packet of SulfaVer 4 Reagent Powder is added to a 10 mL Spring
Creek water sample. The sample then sits for a five minute reaction period.
These solutions
were then put into a spectrometer which calculated the absorption value automatically. Once the
absorption values for the standards were found, they were plotted on a calibration curve to form
a best fit line. Taking the slope of the line and the y-intercept, equations were derived that would
allow for the calculation of concentration. The equations were found to be y = 0.746x + 0.0048
for nitrate and y = 73.168x – 0.892 for sulfate. However, since the nitrate samples were diluted
by a factor of 1:10, the calculated nitrate concentration value had by be multiplied by ten.
The test for alkalinity was conducted by using a titrator to add acid (1.6 N H2SO4) one
drop at a time until the pH of the sample reached a value of 3.5. The number of drops was
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recorded as well as the volume of acid added and these values were used in the Gran Method to
make a calculation of the alkalinity for each sample.
Results:
pH Trend
10
9
8
7
pH
6
5
4
3
2
1
0
0
10
20
30
40
50
Locations Along Spring Creek
Figure 1: A line graph that shows the steady increase in pH values as Spring Creek moves
further and further downstream.
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Conductivity Trend
800
700
Conductivity (µS)
600
500
400
300
200
100
0
0
10
20
30
Locations Along Spring Creek
40
50
Figure 2: A line graph that displays the relatively large increase in conductivity as Spring Creek
travels further downstream.
Temperature Trend
Temperature (degrees Celsius)
30
25
20
15
10
5
0
0
5
10
15
20
25
Locations Along Spring Creek
5
30
35
Figure 3: A line graph showing the slight increase in water temperature as Spring Creek travels
downstream.
Nitrate Concentration in Spring Creek
4.5
Nitrate Concentration (mol/L)
4
3.5
3
2.5
2
1.5
1
0.5
0
-0.5
0
20
40
60
80
100
Location on Spring Creek
Figure 4: A line graph with a best fit line showing the increase in nitrate concentration as
Spring Creek flows downstream.
Sulfate Concentration in Spring Creek
Sulfate Concentration (mol/L)
80
60
40
20
0
0
10
20
30
40
50
-20
-40
-60
Locations on Spring Creek
6
60
70
80
Figure 5: A line graph containing a best fit line displaying the increase in sulfate concentration
as Spring Creek flows downstream.
Spring Creek Alkalinity
5.00
4.50
Alkalinity (meq/L)
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
0
5
10
15
20
25
Locations Along Spring Creek
Figure 6: A line graph with a best fit line representing the increase in alkalinity as Spring Creek
flows downstream.
Discussion: After evaluating all the measurements that were taken (pH, conductivity,
temperature, nitrate concentration, sulfate concentration, and alkalinity), it’s discovered that each
of these measurements increases as Spring Creek flows downstream to lower elevations.
However, this is no coincidence. The increases visible in figures 1-6 are mostly due to
environmental factors such as the lithology of the watershed but are also an effect of human
alteration to the environment. Figure 1 shows an increase in pH as the creek moves downstream.
This increase is due in large part to the amount of limestone that is present at lower elevations of
the watershed. Limestone is calcareous and is known for it’s ability to raise the pH of a solution
which explains why samples from lower elevations that are more exposed to limestone have
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higher pH values. Conductivity in water is greater whenever more inorganic substances such as
calcium, chloride, sodium, and sulfate are dissolved in it. Just like pH, the conductivity increases
as the creek moves to lower elevations because the limestone contains inorganic calcium which
triggers an increase in the conductivity. Figures 4 & 5 exhibit an increase in both nitrate and
sulfate concentrations moving downstream. Irrigation is a common cause for high nitrate and
sulfate levels. This theory supports the rise in nitrate and sulfate levels that we’ve come across at
lower elevations in the watershed because at lower elevations the land is much flatter and farm
land is very common, especially in Central Pennsylvania. Farmers irrigate their crops and the
irrigation water runs off the land carrying nitrate and sulfate from the soil and eventually ends up
in Spring Creek. Looking at Figure 6, it’s quite clear that there is an upsurge in alkalinity at
lower elevated locations along the creek. The best explanation for this is that the stream is
exposed to large amounts of limestone and dolostone at the lower elevations. This lithology
contains high calcium carbonate content which is a direct cause of high alkalinity. It is also
possible that calcite and dolomite can be leached from the surrounding farm land and dissolved
in the creek water (Addy, 2004).
Conclusions: Through data collection, measurement, calculations, and the evaluation of the
results, I am now able to better understand the chemical makeup of Spring Creek and the reasons
that the composition is the way that it is. I have concluded that the unique water composition is
mostly due to the lithology of the environment but can also be attributed to human activity
around the watershed. This series of labs has uncovered a lot of useful information about the
composition of Spring Creek that can hopefully help out geochemists in future studies of the
watershed.
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Acknowledgements: I would like to acknowledge and extend thanks to the following persons
who have made the completion of this research possible:
Dr. Matthew Fantle, Megan Pickard, and Matt Gonzalez for giving me the knowledge to fully
understand all of the concepts needed to complete a full analysis of Spring Creek.
My fellow Geoscience colleagues for making accurate measurements and calculations that were
used in this lab.
The Geoscience Department for supplying me with all of the tools and instruments necessary to
carry out this research.
References:
Addy, Kelly; Green, Linda; and Herron, Elizabeth. “pH and Alkalinity.” University of Rhode
Island. July 2004. http://www.uri.edu/ce/wq/ww/Publications/pH&alkalinity.pdf.
PGWA (Pennsylvania Groundwater Association). “The Spring Creek Watershed.” August 2011.
http://pgwa.org/the_spring_creek_watershed.htm.
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