Effects of Phosphate Fertilizer on Lotic WQI Tests

Matt F., Matt B. , Brittany, Garrett

1. Background2. Introduction3. Experimental setup4. Materials used5. Data Analysis6. Discussion

Overview

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

“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

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 & pHWeek 2: Final Turbidity & pH; Initial DO/BODWeek 3: Final DO/BOD

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”

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.

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

Materials Used:Equipment/Supply List

● 6 Biochemical Oxygen Demand (BOD) Bottles

● Lab quest

● Lab quest Dissolved Oxygen (DO) Probe

● Vernier

● Turbidity Sensors

● pH Sensor

● 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:

.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:

.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:

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:

.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:

Discussion:WQI Test Average

CalculationsDifference Comments

pH Control → 3.06Experimental → 3.5

.44 pH difference Higher pH for experimental

BOD Control 9.2mg/L 8.8mg/LExperimental 9.0mg/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 NTUExperimental → 138.4 NTU

3.5 NTU difference Increase fertility = increase in turbidity

Predictions

Test Prediction ResultpH 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

Experiment limited by:● Time● ResourcesFuture Experiments:● Lotic & Lentic Sources● More Samples of Water● All 9 WQI Tests Run

Future Experiments