What’s In Your Water?

Megan Proulx and Chase Houser

Basha High School

Introduction1. In the article, “Does Tap Water Have More Minerals Than Filtered Water?” it

states that tap water contains essential minerals, such as calcium, magnesium, and iron, that are vital to human development and health. (http://www.livestrong.com/article/345301-does-tap-water-have-more-

minerals-than-filtered-water/)2. This articles explain what types of bacteria can survive and live in distilled water.

Endospores are hardy bacteria cells that can withstand extreme conditions, such as high heat and acidic environments. They can reproduce quickly in water. (http://pscantie.myweb.uga.edu/definition.html)

3. Bottled water is regulated by the FDA; it monitors where the company claims it gets its water and forces them to measure levels of contaminant/minerals. Also, it defines distillation: water is vaporized and collected (minerals are left behind because they do not turn into vapor) and reverse osmosis: water is pushed through a membrane, thus removing the impurities. Companies market the bottled water as purified and safe. (http://www.ncsu.edu/project/bio183de/Black/chemreview/

chemreview_news/402_h2o.html)

Introduction (cont’d)4. Distilled water has been cleaned, and the majority of the minerals are

filtered out. Distilled water goes through multiple distilling processes that eliminate almost all minerals. Distilled water should not be drank as primary source of water because it can lead to the swelling of cells, causing them to explode in extreme cases. Also, it does not contain any minerals beneficial to health. (http://www.differencebetween.net/science/nature/difference-between-

distilled-and-purified-water/)5. Legionella pneumophila is a bacteria commonly found in the metal

piping of underground water systems. Also, it thrives in drinking water systems. This is an example of bacteria that grows in water– especially tap water. (http://www.epa.gov/nerlcwww/research/pathogens.html)

6. Aquafina receives its water from public water sources and is purified through multiple cleansing processes. Cleansing processes include reverse osmosis and carbon purifier. (http://www.aquafina.com/purity-guaranteed.php)

Research Question/Hypothesis

• Research Question: What type of water will grow the most amount of bacteria in a week? This is important to ensure that people are drinking the healthiest

water that is most resistant to bacteria, which can cause illness. • Hypothesis: If samples of purified, distilled, and tap water

are placed in petri dishes, then the tap water will grow the most bacteria because tap water is poorly filtered and cleaned, while the distilled and purified are cleaned through multiple processes, such as osmosis and/or distillation. The experiment has the potential to point out false information

given by companies on cleaning processes and prove which type of water is best for daily consumption.

Experimental ProcedureMaterials:•Scale•*Water Quality test kit•Distilled water•Bottled Water (Aquafina)•Tap water•Agar powder•Weight boat•Spatula•Inoculating loop•Sharpie•Bunsen burner•Lighter•Petri dishes (9)•Microwave•Beakers (3)

1. Gather all materials.2. Create an agar solution to place in nine petri dishes (follow

directions on bottle). Microwave for about 30 seconds to one minute. Pour into petri dishes. Let cool.

3. *Test each sample of water using water quality test kit. Record results.

4. Pour enough water into three beakers to submerge inoculating loop.

5. Once agar has solidified, turn on Bunsen burner. Hold inoculating loop over hottest part of flame until red hot.

6. Then, quickly dip it into one type of water and swab gently on agar of one petri dish. Make sure not break the agar.

7. Repeat step five 8 more times, resulting in three trials of each type of water

8. Before and after each swab, hold inoculating loop over Bunsen burner to burn off all airborne/waterborne bacteria.

9. Cover trials with lid and secure with tape. Label.10. Observe each trial every day for a week. Observe the

amount of bacteria grown. Record.

*later omitted from experiment

Experimental procedures (cont’d)• Control group: distilled water

• Three trials of each water were conducted to be able to average the amount of bacteria grown if a trials was inaccurate or unsuccessful (i.e. agar melted, not enough water was placed on agar)

• The inoculating loop could have gathered excess amounts of bacteria if it was not heated up enough or left out leaving it exposed to the air. That is why the loop was heated before and after each trial, killing bacteria. Also, each water was poured into a beaker before swabbing onto the agar, causing it to possible me contaminated with preexisting bacteria.

Results (cont’d)

Type of water

Measured in parts per million

Purified Distilled Tap

pH Safe (8.5) Safe (6) Caution (5)

Alkalinity Safe (240) Low (0) Ideal (80)

Chlorine Safe (.2) Safe (0) Safe (0)

Hardness Harder (250) Soft (0) Soft (0)

Copper Safe (0) Safe (0) Safe (0)

Iron Safe (.1) Low (0) Low (.1)

*This data was later thrown out and not used in the experiment becausethe lack of accuracy and the incorrect data found. The amount of minerals other levels in each other were researched and collected.

Results

Amount of visible bacteria (observations)

Purified Distilled Tap

Trial One Cloudy, penny sized colony

White, penny sized colony; another cloudy portion covered about 80% of lid

Cloudy bacteria, covered around 75% of lid

Trial Two None; no visible bacteria grew

None Three cloudy, half-penny sized colonies, half-penny sized yellow colony

Trial Three White, dime sized colony

Yellow, dimed sized colony

One cloudy, penny sized colony, one half penny sized cloudy colony

Results (cont’d)• 2/6/13:

no bacteria grown in any trials• 2/7/13:

Distilled (trial one, trial three): white colony appeared in both Tap (trial one, trial three): white clouded bacteria beginning to form All other trials remained clear

• 2/8/13: Distilled (trial one): white colony grew to penny size, Distilled (trial three): white colony turned yellow Purified (trial three): small cloudy colony grew All other trials remain clear

• 2/11/13: Distilled (trial one): cloudy bacteria covers around 75% of lid Distilled (trial two): none Distilled (trial three): darkening of colony Purified (trial one): cloudy colony grew to penny size Purified (trial two): none Purified (trial three): white colony darkens Tap (trial one): cloudy bacteria covers around 60% of lid Tap (trial two): two half penny sized cloudy colonies, formation of yellow colony Tap (trial three): two beginnings of white colonies

Results (cont’d)

Before

After

DiscussionTap

•Had the most bacteria at the end of the experiment because it is the least filtered does not undergo multiple cleaning processes such as reverse osmosis, distillation which

then leaves behind many more forms of bacteria and minerals Some of the minerals left behind serve as a nutrient base to breeding bacteria With food and water available, plus a heat source, the bacteria were able to reproduce

easily and quickly

Distilled

•Had the second most bacteria at the end of the experiment because the boiling process does not kill all the bacteria

Distilled water is cleaned through a boiling process which involves heating the water up to 100°C (212°F). The extreme heat often kills most bacteria, however, stronger, more heat-resistant bacteria can still survive the process- specifically endospores. Some can survive up to 250°F.

The distilling process of the water likely did not exceed the boiling point, leaving behind some traces of bacteria which then were able to breed. Since endospores are very resistant, they were able to multiply in the petri dish at a much faster rate.

Discussion (cont’d)

Purified•The purified water (Aquafina) had the least amount of bacteria because it is purified through numerous cleaning processes:

Aquafina says they clean their water through the “HydRO-7™ Process” which involves:

– static mixer (prevents stagnation of water)– polishing filter (removes smaller particles),– UV (eliminates organic matter)– reverse osmosis (removes solids)– activated carbon purifier (isolates elements that are in small amounts)– polishing filter (clarifies water)– ozone generators1. All these processes remove up to 99.9% of contaminants. This killed almost all

bacteria, did not provide a solid nutrient base, and completely cleaned the water. The purified samples did not provide a good breeding habitat for any sort of bacteria.

Conclusion

• The overall findings were that both the distilled and tap water easily grow bacteria when compared to bottled water, which does not all for bacteria to grow as easily. The findings are important to make people aware that they should not drink any type of pre-opened, older water as bacteria are more than likely growing in it (such as a glass of tap water sitting on a nightstand from two days ago). Also, it details the things in water that people are drinking: higher levels of bacteria/minerals in tap, and more resistant bacteria/no minerals in distilled. On the other hand, bottled water provides some minerals (in very small amounts) and less bacteria than tap.