Water Bottle/ Bacteria Correlation Biology Experiment... 10 POINTS?

Question

OK, my topic is along the lines of is it safe to use a regular 16.9 fl oz water bottle over and over and over again, or does the amount of bacteria increase after each refil and use, therefore not being safe...

OK, how the heck do I go about measuring this? Microscope? If so how?

If this doesn't work out, atleast give me some other biology topics that does not involve any plants.

Answer 1

Sounds like a good question, but might be a bit difficult to test, depending on what kind of a lab you have.  First of all, though, bacteria and "safe" are not necessarily correlated.  Lysol and other companies will have you believe that you need to kill all bacteria to keep your family safe, but the reality is that most bacteria are perfectly safe unless you start directly injecting them into your blood stream or open wounds.   Most dangerous bacteria are spread from other infected animals or persons, not stuff that spontaneously grows in water bottles and such.  So a nasty old water bottle may smell bad, but may be perfectly safe if you're not sharing it with sick friends.  

Probably you would have some bacteria build up over time--they often form what's called a biofilm on the surface of things underwater--increasing over time until they hit a carrying capacity.  I fear that testing this might be difficult for the amateur.  Usually bacteria are measured with colony counts, where you dilute down a solution containing an unknown number of bacteria, smear it on an agar dish, and incubate it, and later return to count the "spots" formed by the colonies.  You can see bacteria under a microscope, but you need a good microscope and the right kind of dye.  And even if you have that, it's difficult to get an accurate count on a microscope slide, which  is hard to control the volume of medium you are measuring the bacteria in.  Ultimately, you are counting the number of bacteria per unit area or per volume of water, in which case you need to accurately know an area or volume.  I'm not an expert at this, but I am telling you my intuition based on a degree in biology.  

I don't completely understand if you topic is limited to safety of water bottles?  Difficult topic (still an active area of research and public health for professionals, but difficult for a single student to tackle).  If that's not the case, then how about this: An example of something microbiology-related that might be easier to measure in a home lab? How about something like the amount of CO2 generated by yeast. You could capture it in baloons or a bubble trap. All you need is yeast and a sugar solution and some bottles and tubes. You could test the effects of different temperatures, or different sugar concentrations, or different types of sugar. That way, you don't actually have to count the yeast, which can be very difficult to do, but you can measure an easy-to-capture byproduct...the CO2 that bubbles off.

  Just a thought and good luck.

Answer 2

You can measure the pH,Nitrate,Phosphate,Dissolved Oxygen (ect.). If these levels decrease or increase it could be a good or bad thing. Search how to find the pH,Nitrate(ect.) on google. You will also need a chart to see your results.( chart http://staff.jccc.net/PDECELL/chemistry/... a good pH is 7 (neutral)). (Nitrate chart http://www.americanaquariumproducts.com/... Phosphate chart Couldn't find). (Dissolved Oxygen http://www-tc.pbs.org/safarchive/images/... For this you'll need test tubes and TesTab. Good Luck!

Answer 3

Should you re-use plastic bottles? There is a lot of recent controversy  surrounding plastics and health.   I will give you some info, you decide what is right for you.  As always there are studies that have reached far different conclusions regarding plastics.

Plastics some say we should avoid

#3 Polyvinyl Chloride (PVC) commonly contains di-2-ehtylhexyl phthalate (DEHP), an endocrine disruptor and probable human carcinogen, as a softener.

#6 Polystyrene (PS) may leach styrene, a possible endocrine disruptor and human carcinogen, into water and food.

#7 Polycarbonate contains the hormone disruptor bisphenol-A, which can leach out as bottles age, are heated or exposed to acidic solutions. Unfortunately, #7 is used in most baby bottles and five-gallon water jugs and in many reusable sports bottles.

Some say these are better choices

#1 polyethylene terephthalate (PET or PETE), the most common and easily recycled plastic for bottled water and soft drinks, has also been considered the most safe. However, one 2003 Italian study found that the amount of DEHP in bottled spring water increased after 9 months of storage in a PET bottle.

#2 High Density Polyethylene

#4 Low Density Polyethylene

#5 Polypropylene

Some say these are the best choice if you plan on re-using

bottles: Betras USA Sports Bottles, Brita Fill & Go Water Filtration Bottle, Arrow Canteen

Better choice for baby: Choose tempered glass or opaque plastic made of polypropylene (#5) or polyethylene (#1), which do not contain bisphenol-A.

As for bacteria

The dose equals the poison.  Bacteria are all around us, what may make one person ill may have no effect on another.  If you have not had any gastrointestinal illness since re-using your plastic bottle then I would not worry about it.  

You can check your bottle for contamination with a product called Colilert, made by IDEXX. Hopes this helps