Tap Water Intrusion Effects on Microbial Life Anthony DeRenzo Grade 10 Pittsburgh Central Catholic High School

Surface Runoff Is part of the water cycle and describes the water that flows over a land surface. Can come from precipitation and flow into natural bodies of water. It can have an effect on the marine life in the various water sources it enters.

Types of Surface Runoff Petroleum Pesticides Many organic and inorganic chemicals Silt Fertilizers Tap Water

Water directly drawn from a faucet Used in everyday appliances such as washing machines, dishwashers, and showers. Contains a wide variety of components.

Sodium Nitrate A colorless, odorless crystalline compound. Formed by a chemical reaction of sodium chloride and nitric acid. Used in the production of explosives, fertilizers, and potassium nitrate, and also is used in the preservation of meats.

Relationship People make use of sodium nitrate by growing plants with fertilizers. People make use of tap water through sewage systems, plumbing, and many other activities. A fraction of these two substances undoubtedly enter natural water sources. There are numerous species of macroscopic and microscopic organisms that could be affected by runoff that contains either sodium nitrate or tap water.

Saccharomyces Cerevisiae A type of yeast that reproduces by budding. The most useful yeast. It is used in baking and brewing. A eukaryote that shares the complex internal structure of plants and animals.

Escherichia coli A type of bacteria that is found in warm-blooded animals. It can be found in the fecal matter as well as the intestines. Some strains posses flagella and other do not. It can grow by both aerobic and anaerobic respiration.

Purpose To test different concentrations of tap water with a controlled concentration of sodium nitrate on two forms of microbial life: Saccharomyces cerevisiae and Escherichia coli.

Null and Alternative Hypotheses Null: sodium nitrate will not significantly affect the population survivorship of Saccharomyces cerevisiae or Escherichia coli. Null: the addition of different tap water concentrations will not significantly affect the population survivorship of Saccharomyces cerevisiae or Escherichia coli. Alternative: the addition of different concentrations of tap water with the controlled concentration of sodium nitrate will adversely affect the microbial models.

Materials 40 YEPD and 40 LB agar plates container of ethanol 5 spreaders 8 SDF culture tubes 1 ml of sodium nitrate 17 ml of tap water 5 ml pipette and micropipette 0.22 micron syringe filter cultures of Saccharomyces cerevisiae and Escherichia coli

Procedure 1 The experimental variables, tap water and sodium nitrate, were sterile filtered with 0.22 micron syringe filters. Samples of the microbial cultures were taken and diluted in a sterile dilution fluid to a concentration of 10 3 cells/ml. The experimental variables were added to the tubes with SDF solution to create the chosen concentrations of 0%, 10%, 25%, and 50% of tap water and.1% of sodium nitrate in each group. Also, 0.1 ml of the microbial cultures was added to the tubes to create a volume of 10 ml in each tube. There were four concentration groups for each microbial culture (chart on next page), and two tubes made for each group.

Procedure 2 Group 1Group 2Group 3Group 4 Tap Water 0 ml1 ml2.5 ml5 ml SDF9.8 ml8.8 ml7.3 ml4.8 ml Sodium Nitrate 0.1 ml Microbe0.1 ml

Procedure 3 The solution for each group was vortexed and allowed to sit at room temperature for 1-2 minutes. After vortexing, 0.1 ml aliquots were removed from the tubes and spread on the YEPD agar plates (S. cerevisiae) and the LB agar plates (E. coli). The plates were set at room temperature and grown for six days. After six days, the number of surviving colonies were counted from each plate.