Purpose
The purpose of this laboratory was to use field methods to assess water
quality at four locations along the Bushkill Creek. We also analyzed
our results based on geology, hydrology, and land use.
Theory
Alkalinity, pH, temperature, conductivity, and dissolved oxygen content
are good indicators of how suitable a body of water is for aquatic life
and recreational use.
Apparatus
pH/temperature
meter, conductivity meter, Hach test kit for DO
Procedure
1.
At each sample location, we used hand-held meters to measure pH, temperature,
and specific conductivity. We also used the Hach test kits to determine
dissolved oxygen.
2. We checked that the pH meter was calibrated to the pH 7.0 buffer solution (yellow).
3. At each location, we collected a “grab sample” from the stream with a plastic cup, making sure the water was taken from a location with visible flow, not a stagnant pool.
4. We placed the pH/temp and conductivity probes in the plastic cups, being careful to not stick the probes directly in the stream. When the readings stabilized, we recorded them. Each location was sampled twice for pH/temp and conductivity.
5. We then used the Hach test kits to determine DO:
a.
Collected a stream sample in the bottle provided, being careful not to
trap any air bubbles when we inserted the stopper.
b.
Added one of each reagent packet, then inverted the bottle several times,
allowing the precipitate to settle halfway.
c.
Inverted again, and allowed it to settle.
d.
Added the contents of the plastic pillow; the precipitate should disappear
and the sample should turn yellow.
e.
Filled the small tube from the bottle, then transferred into the small
glass container
f.
Added sodium thiosulfate drop by drop, counting the number of drops until
the solution went clear
Results and Discussion
Table
4: Results of field sampling from four locations on the Bushkill Creek
Sample
Location Temp(deg C) pH
Conductivity(mS/cm) DO(mg/L)
2
13.6
7.4
560
10.5
3a
15.6
8.6
724
10
3b
14
7.7
529
10
7
13.6
6.9
163
10
Diagram
1: Map of Sample Locations
**
for a picture of the map, click here
Description
of Sample Locations:
2
= Catch and Release Area, Near Binney & Smith
3a
= Shoeneck Creek at confluence
3b
= just about mouth of Shoeneck Creek
7
= Sobers Run north of Jacobsburg SP office
From the results obtained from the field-testing we were able to determine
the impact of hydrology, geology and land use on the Bushkill Creek.
For example conductivity is the result of total dissolved ions (TDS) in
solution. High conductivity may indicate contamination with salts
or inorganic wastes. At location 3a (Shoeneck Creek at confluence), the
conductivity is 724 mS/cm. This is the highest conductivity we obtained
and we attribute this sudden increase to the wastewater treatment plant
located in this region. At the same location we see the highest
pH of all the sample locations, which is attributed to excess slate found
in the region.
The Dissolved Oxygen content remained consistent at all four locations.
Since the temperatures were consistent and only varied by 2 degrees Celsius
the results from the Dissolved Oxygen test seemed reasonable.
This is due to the fact that high temperatures may result in low levels
of dissolved.
The locations of the stream appears to have the best quality are location
2, 3b, and 7. This is because the pH values fall within the healthy
range of 6 to 8.5. The conductivity of these three locations is healthy,
since the conductivity of pure water is 500 mg/L. We can attribute
the sudden drop in conductivity of location 7 to a possible increase in
flow rate. High flow rates tend to dilute the concentrations of dissolved
solids.
The location that appears to have to worst quality is that at location
3a. This is because of the high pH of 8.6 and high conductivity of
724.
