Experiment outline on Tap Water vs Bottled Water

[Lemm]

Im currently a junior at my high school, and i am planning on performing an experiment in which i will compare local tap water to locally bottled water and see if there is any scientific justification for paying more for bottled water. I have done some research on the aspect and have found the regulations that the tap water distribuition company has to abide by, these include aspects like hardness, total fecal coliforms, chlorine levels, lead, etc...

I would appreciate any guidance in which aspects of the water to test and compare, the most important ones that have a bigger effect on the quality of the water, for example the hardness, chlorine levels, and such. I was also planning on possibly testing 3 locally bottled brands of water and a number of tap water samples from different areas in the city (Maybe 3 or so) for more accuracy.

Basically i need advice on how to outline my experiment and possibly which parameters to test, also i considered maybe testing 2 different shipments of the bottled water allong with testing tap water from different locations to improve accuracy and see if the results are consistent.

Im planning on discusing this further with an advisor at my local university, but I don´t want to walk in blank on how exactly is the experiment going to be structured.

Thanks for all the help, Hope you all had good holidays.

 

[eli64]

your variables to test sound good but just wondering where and how you were planning to do these tests? Some of these parameters need fairly sensitive equipment and possibly expensive chemicals (for a high school lab) to test to the accuracy needed to distinguish the differences. Is your advisor at the Univ going to be the supervisor of the testing?

some of these http://www.fws.gov/chemistry/methods_let_lab.htm#MethodCode005" describes a special solution for choliform testing.

pH testing and water hardness might be feasible for basic lab setups

 

[Kushal]

you might also find a way to test for bacteria or germs (or living organisms in general) present. i dunno, maybe using microscopes??!

and for minerals and nutrients?? do plants getting tap water or bottled water grow differently??

if you store tap water and bottled water in a certain recipient (not the bottle of course), which one lasts longer.

i'm jjust suggesting some ideas, some of which mat seem weird...lol...

hardness and some 'contents' (e.g. ions, chlorine,...) are nice variables.

good luck

 

[Lemm]

Yea i was sleeping earlier, but I already arranged it with my local University and they agreed to allow me to use their lab and the advisor will supervise my progress. I am going to call her now and setup a meeting... ill post again once i get more information.

Right now I am just wondering how many water samples do i need, I am thinking of going with 2 bottled water samples possibly two different shipments and posibly 4 samples as well from tap water from different locations so i can generalize my results to some extent.

 

[eli64]

Right now I am just wondering how many water samples do i need, I am thinking of going with 2 bottled water samples possibly two different shipments and posibly 4 samples as well from tap water from different locations so i can generalize my results to some extent.

not sure why you would need different shipments, are you looking at quality control for a company's product too?

I think sticking to your first premise to begin with, why pay for bottled water vs tap, would reveal more about marketing than safety reasons that people buy bottled water.

You could start out with 3 samples: tap, high and low end domestic bottled (spring or filtered?)

for tap water collection, I think there are suggested specs for the collection bottles to minimize contamination.

then you can get into domestic spring water vs Evian or even the carbonated version...