Determining the Effect of pH Levels in the Surrounding Environment

Abstract

This experiment was designed to determine if surrounding factors affect the pH of bodies of freshwater and how pH can affect the environment. Five samples of water were taken from various bodies of freshwater. Their pH levels were measured using pH paper and compared on a data table. It was hypothesized that areas that were more densely populated in the surrounding would have a lower pH level, making it more acidic. This was proven true. Areas such as the canal in the backyard of a popular neighborhood and the recreational swimming and boating area (Lake Weir) had lower pH levels than conserved areas with less dense populations surrounding them such as Silver Springs and Lake Geneva.

Introduction

PH is a measurement of the activity of Hydrogen ions in a substance. PH is measured using either a pH meter (an electronic probe) or litmus paper. The pH scale ranges from 0 to 14 with 7 representing neutral. Substances with a lower pH level are more acidic. Substances with higher pH values are more basic. Many factors affect pH such as the amount of CO2 in the substance, types of rock and soils surrounding the substance, drainage, air pollution, temperature, amount of minerals, acid rain, wastes, salinity, etc. Acid rain is a result of the mixture of combusted fossil fuels mixing with atmospheric water. (Boyd) Cars and electrical power plants are contributors to acid rain. With acid rain, the soil absorbs aluminum causing plants to be less able to absorb nutrients. Acidic water also destroys food sources, including microorganisms. In this experiment, lakes that are more densely populated in its surrounding areas will have a more acidic pH. Why does pH matter? High levels of acidity affect both plants and animal life in an ecosystem.

Materials and Methods

Materials

• pHydrion INSTA-Chek 0-13 pH paper (ripped into 5mm sections for each trial)
• Lead pencil
• College ruled lined paper
• 50 ml distilled water
• Metal forceps
• 50 ml of water from 5 different lakes (lakes listed in data table)
• 6 200 ml Pyrex beakers
• 35 plastic Ziploc bags
• Mercury thermometer
• Latex gloves

Figure 1: Demonstrates uncertainty for the equipment used in the experiment

Equipment Name Uncertainty

200 mL Pyrex beakers +/- 50 mL

pHydrion INSTA-Chek 1-13 pH paper +/- ½ pH

Mercury thermometer +/- 1oCelcius

Methods

50 mL of water was collected from each body of freshwater in a 100mL beaker. A 5mm piece of pH paper was carefully torn from the roll. Using tongs, the pH paper was cautiously placed into the 50mL of water for five seconds. The paper was then removed and the color was compared to that INSTA-CHEK pH comparison chart on the front of the packaging.

The pH paper was then placed into a separate Ziploc bag specific to its trial and location. The pH level was recorded and the process was repeated seven times altogether at each body of water. Five separate bodies of water were tested.50 mL of distilled water was placed into a 100mL beaker to use as a control against the pH levels of the freshwater.

Results

Figure 2: To show pH variations upon bodies of freshwater in Marion County, Florida with standard deviation.

Name of Body of Water Trial 1 Trial 2 Trial 3 Trail 4 Trial 5 Trial 6 Trial 7 Average

Lake Weir 6 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 6 +/- ½ pH 7 +/- ½ pH

Canal Behind House 6 +/- ½ pH 6 +/- ½ pH 6 +/- ½ pH 6 +/- ½ pH 6 +/- ½ pH 6 +/- ½ pH 6 +/- ½ pH 6+/- ½ pH

Lake Geneva 7.5 +/- ½ pH 7.5 +/- ½ pH 7.5 +/- ½ pH 7.5 +/- ½ pH 7.5 +/- ½ pH 7.5 +/- ½ pH 7.5 +/- ½ pH 7.5 +/- ½ pH

Rainbow River 7 +/- ½ pH 7 +/- ½ pH 7.5 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH

Silver Springs 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH

Distilled Water 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH

Figure 3: To show processed data corresponding to Figure 1 with standard deviations

(Mean, Median, Range, and Mode).

Name of Body of Water Mean/Average (all of the values added together and divided by seven) Median (numbers listed in numerical order and one crossed off of each side until the middle is reached) Mode (value that occurs most often in a group of data) Range (difference between largest and smallest values)

Lake Weir 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 1 +/- ½ pH

Canal Behind House 6 +/- ½ pH 6 +/- ½ pH 6 +/- ½ pH 0 +/- ½ pH

Lake Geneva 7.5 +/- ½ pH 7.5 +/- ½ pH 7.5 +/- ½ pH 0 +/- ½ pH

Rainbow River 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH .5 +/- ½ pH

Silver Springs 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH

Distilled Water 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH 7 +/- ½ pH

Figure 4: Graphs Processed Data for Comparison for Each Trial

Conclusion and Evaluation

The data in figures 2, 3, and 4 demonstrate that my hypothesis was supported. Bodies of freshwater with more populated residential surroundings have lower pH levels, making them more acidic showing the effects of contamination. For example, Rainbow River had a higher pH level than the canal in the backyard. Rainbow River is a conservational area with little to no residential areas surrounding it, the canal on the other hand was highly populated with surrounding residential dwellings.

The data was inconsistent. The experiment occurred over a period of five days, during those five days, the temperature fluctuated which could have been a cause of the data’s inconsistency.

The experiment had many limitations causing problems and inconsistency in the data. The temperature for each body of water for each trial should have been taken to make sure that during each trial the temperature was held constant. Also it should have been made sure that the temperature was the same within the bodies of water. Since temperature is a direct effect on pH levels, this could have caused a problem in the data. Also, a pH probe should have been used since pH probes are more accurate than pH paper. PH paper can be inaccurate because sometimes it is hard to match the color of the strip with the colors shown on the label on the box. PH paper also gives an estimate in increments of ½, meaning the scale rounds the pH value to the nearest ½ instead of giving an exact pH value, as a pH meter would.

Overall my design was significant for the job, but it was uncertain which variable was the independent variable due to the temperature changes. Since the pH was not constant throughout every trial, more trials should have been done to make the average pH for each body of water more accurate. To improve this experiment, an electronic pH meter should have been used since it gives a more accurate reading than pH paper. The water should be measured more accurately on a flat surface to be able to measure the meniscus; therefore the amount of water remains a constant instead of becoming yet another independent variable. Also, keeping the temperature constant by measuring the temperature before every trial with a thermometer would make the experiment more accurate.

Aknowledgements

Thanks is given regarding this paper to Temayla Vishudinad for peer editing my paper.