3. Phosphate fertilizers
- Commonly used in agriculture.
- In a study conducted by Tiamtanon et al. (2015), it was found that
the fertilizers increased nutrient intake in mycorrhizal fungi by
increasing spore number, root colonization density, and phosphate
activity.
The Problem
- Runoff from these fields often winds up in local water sources and
have negative effects.
- Increases eutrophication while killing aquatic life.
- This occurs in both urban and agricultural settings.
Background
4. “To see the effect it has first hand, we collected water from
a lotic water source and added phosphate fertilizer directly
into the water. We then measured the effects of the
fertilizer on pH levels, Dissolved Oxygen, Biochemical
Oxygen Demand, and Turbidity. Through these four
measurements we ultimately measured how the addition of
phosphate fertilizer changed the Water Quality.”
Background
5. Introduction:
.Phosphate Fertilizers Impacts:
.Increase in pH
.Limiting factor which means eutrophication
.Measured the Water Quality Index on four variables:
-Turbidity
-pH
-DO
-BOD
.Time Line: Week 1: Initial Turbidity & pH
Week 2: Final Turbidity & pH; Initial DO/BOD
Week 3: Final DO/BOD
6. Introduction Continued:
. Our prediction:
.Increase in phosphate fertilizers
=pH increase
=DO decrease
=BOD increase
=Turbidity increase
.Our Hypothesis:
“The purpose of this experiment is to test how phosphate fertilizer will affect
certain parameters of the WQI of a lotic water source. We will be testing how
changing the quantity of phosphate fertilizer will affect the lotic water’s pH, DO,
BOD, and turbidity”
7. Experimental Set Up
.Water collected on March 21, 2015 at 1330 hours,
Manalapan, NJ.
.6 1.4L aquariums were set up, three were the control
and the other 3 were the experimental group
.1L of water was poured into each aquarium.
.Experimental tank received 2.5g/L of Phosphate fertilizer
.Fertilizer was the independent variable; WQI variables
were the dependent variables.
8. Experimental Design Parameters Effect of Phosphate Fertilizer on
WQI Test
Independent Variables Phosphate Fertilizer
Dependent Variables Turbidity, pH, DO, BOD
Controlled Variables Temperature, Volume, Sunlight, Amount of
fertilizer
Controlled Groups No phosphate fertilizer in 3 tanks
Experimental Groups Phosphate fertilizer in 3 tanks
10. ● 4 cuvettes with one of them being the blank/test buffer for calibration
● Turbidity sensor
● P 200
● P 1000
● P 20
● SpectroVis
● Amount of Phosphate Fertilizer 2.5g/L
Materials Used:
11. .For our Turbidity test, the mean (+/) 1 SD for the control group was 103.9 (+/) 15.0 NTU. The
experimental group had a mean (+/) 1 SD of 138.4 (+/) 8.34 NTU. N=6. The difference between the
samples means of control and experimental Turbidity values was statistically significant (p=.037). The
experimental had a higher mean (+/) 1 SD than the control.
.In terms of WQI, the control group values gave a Turbidity Q-value of 15, while the experimental
group generated a Q-value of 5. Therefore, the amount of phosphate fertilizer that we added to our
experimental water samples lowered the WQI of those samples by increasing the turbidity.
Data Analysis:
12. .For our pH test, the mean (+/) 1 SD pH for the control group was 3.06(+/)0.02. N=6. The
experimental group had a mean (+/) 1 SD pH of 3.54(+/) 0.047..The T-test of the difference between
the mean pH values of these two groups resulted in a p-value of 0.0009. Since the p-value was less
than 0.05, the difference between the mean pH values for the groups was statistically significant.
.In terms of WQI, the control group values led to a Q-value of 4, while the experimental group resulted
in a Q-value of 5 for pH. Therefore, the amount of phosphate fertilizer that we added to our
experimental water samples benefitted the WQI of those samples by increasing the pH.
Data Analysis:
13. For the DO test the mean (+/) 1 SD for the control group was an average mean (+/) 1 SD of 94.9(+/) 4.51% for the control
group and 91.47(+/)2.97% for the experimental group. The p-value was .34, making the results insignificant because p-value was
more than .05. The differences in the means were insignificant.
.The T-test of the difference between the mean DO values of these two groups resulted in a p-value of 0.342. Since the
p-value was greater than 0.05, the difference between the mean DO values for the groups was not significant.
.For our Dissolved Oxygen (DO) test, the mean DO for the control group was 94.9% and the standard deviation was
4.51%. The experimental group had a mean DO of 91.5% and the standard deviation was 2.97%.
Data Analysis:
14. .BOD had an average mean (+/) 1 SD of .40(+/).11 for the control group and .24(+/).09 for the experimental group. N=6. BOD was
insignificant with a p-value of .13.
For our Biochemical Oxygen Demand (BOD) test, the mean change in BOD for the control group was 0.40 mg/L and
the standard deviation was 0.11 mg/L. The experimental group had a mean change in BOD of 0.24 mg/L and the
standard deviation was 0.09 mg/L. The T-test of the difference between the mean changes in BOD of these two groups
resulted in a p-value of 0.13. Since the p-value was greater than 0.05, the difference between the mean changes in
BOD for the groups was not statistically significant.
Data Analysis:
15. Discussion:
WQI Test Average
Calculations
Difference Comments
pH Control → 3.06
Experimental → 3.5
.44 pH difference Higher pH for
experimental
BOD Control 9.2mg/L
8.8mg/L
Experimental 9.0
mg/L 8.79mg/L
Control → .40mg/L
Experimental → .
21mg/L
Fertilizer slowed
BOD dropping factor
of 2x
Dissolved Oxygen Control → 94.9%
Experimental →
91.5%
3.4% difference Increase in fertilizer
= decrease in DO
Turbidity Control → 103.9
NTU
Experimental →
138.4 NTU
3.5 NTU difference Increase fertility =
increase in turbidity
16. Predictions
Test Prediction Result
pH Increase Increase by a 0.44 difference
BOD Increase Slowed the rate of decrease
by a factor of 2x
DO Decrease Decrease by a 3.4%
difference
Turbidity Increase Increase by a 3.5NTU
difference
17. Experiment limited by:
● Time
● Resources
Future Experiments:
● Lotic & Lentic Sources
● More Samples of Water
● All 9 WQI Tests Run
Future Experiments
