Introduction:
In order to ensure that environmental problems are addressed, the EPA, Environmental Protection Agency, was created by Congress in hopes of a continuous balance for the sake of the people. The EPA regulates things such as, the levels of toxicity found in large bodies of water, for the maintenance of health and the environment. Article “Legal Petition Urges EPA to Save Sea Life, Regulate CO2 as Toxic Substance” states, “With the world’s oceans and sea life facing an unprecedented crisis from ocean acidification, the Center for Biological Diversity and former EPA scientist Dr. Donn Viviani today formally petitioned the Obama administration to regulate carbon dioxide under the federal Toxic Substances Control Act.” In achieving this process, levels of toxicity are measured by using aquatic organisms as the indicators. These tests display the concentration of pollutants in water, expressed by the Lethal Concentration, LC50. Guidelines for toxicity testing are set forth by the EPA and must be strictly followed by the laboratories performing the experiments. “We’re asking the EPA to prevent ocean acidification now by regulating CO2 emissions under the same law that helped reduce the chlorofluorocarbons that were causing the ozone hole,” Dr. Viviani said in the article, “ Enviros Petition EPA To Regulate CO2 As Toxic Substance.” Without these regulations, people would potentially be using acidic/toxic water, consequently increasing death rate, for both people and sea animals, and environmental issues all around. Another article, “Ocean Dumping- What’s Allowed”, demonstrates “EPA establishes the environmental criteria for evaluating ocean dumping applications, and designates recommended ocean dumping sites.”
If the EPA was never created by Congress in the 1970s, then how rigid would our environmental condition be right now? If zero concentration is used in the lab, how many daphnia magna would still remain alive? How many daphnia magna will remain alive if we use a great amount of ammonium sulfate? The lower the concentration, the more regulated the water will be, thus keeping the daphnia magna alive.
Methods and Materials
A. In order to measure toxicity levels of Ammonium Sulfate, students used Daphnia magna as the indicator. The daphnia will be exposed to different concentrations to compare the toxicity of various conditions.
B. This experiment was achieved by using:
1. Permanent marker
2. 5 plastic cups
3. 5 pipets
4. 5 ammonium sulfate solutions in labeled containers (0.00%, 0.02%, 0.03%, 0.04%,
0.05%)
5. 5 labeled 100-mL graduated cylinders, each corresponding to one solution
6. Daphnia magna
C. Procedure:
1. label each plastic cup with the concentration of ammonium sulfate
2. In a graduated cylinder, measure 70 mL of ammonium sulfate and pour into each of
cup.
3. Use a pipet to transfer 5 daphnia into each cup (do not drop daphnia, gently expel them into solution.
4. Put 5 cups in a designated location in the room. Allow the to sit for 24 hours.
AFTER 24 HOURS HAS PASSED:
5. Determine the number of daphnia that are alive in each cup.
Sample size: 5 groups, 1 class, 17 students. 5 daphnia per group, 25 daphnia per experiment
Control variable: Concentration of Ammonium Sulfate (NH₄)₂SO₄
Experimental variable: Daphnia magna.
Table 1: Percent mortality of Daphnia in various concentrations of ammonium sulfate after 24 hours.
This table demonstrates the experimental data within 1 out of 5 specific groups in the classroom. This group’s data exhibits the daphnia to all be dead after being in a concentration that is more than 0.00%. The overall mortality rate for daphnia in this specific group can be averaged at 100%.
Table 2: Class data of percent mortality of Daphnia in various concentrations of ammonium sulfate after 24 hours
This table indicates the data results of the experiment within the classroom as a whole. 25 daphnia were given to each group, 5 in each of the 5 cups.
Graph: The Effects of Different Concentrations of Ammonium Sulfate on Daphnia
The graph indicates the visual relative frequency of the deaths of daphnia for every concentration of ammonium sulfate. As displayed, the line is shot way up from 0 to 5 by the 0.02% concentration. The LC50 is demonstrated by the dotted line.
Conclusion:
Using the data as a reference, one can conclude that the higher the concentration of ammonium sulfate, the higher the death rate of the daphnia. This is because as water alternates to a different state, in this case, a higher ammonium sulfate concentration, the creatures who inhabit the water die because they aren’t in their best fit environment, which is natural water. The data trend is definitely not a linear form, but one that is almost curved. Although after 0.02%, the death rate seems to stay consistent with 5 daphnia dying at a time. Only at the water’s natural state, 0.00% ammonium concentration, did the daphnia stay alive. The LC50 of the effects of different concentrations of (NH₄)₂SO₄ is 0.01%.
Hypothesis: My hypothesis was correct. The data above supported the hypothesis because it indicates that the greater concentration of ammonium sulfate that is used, the higher the death rate of the daphnia will be. As the independent variable increased, the dependent variable increased as well. Zero daphnia will remain alive if we use the highest concentration of ammonium sulfate. All of the daphnia will remain alive if zero concentration is used.