Science Buddies: "Ask an Expert"

We are testing runoff on sod using reclaimed water, distilled water and tap water. The experiment calls for us to test with a water quality kit. We have researched and hear concerns about PPCP's. We wonder what the best kind of water quality testing kit would be to use that would pick up what we are looking for. Also, what would you suggest we use as our data? The question we are trying to address is, "Is Reclaimed Water safe for School Lawns?" We find information already that the levels of exposure is so low that there would be little to no harm even over hundreds of years. Can you give us some feedback on this? Feel a little shaky on this experiment that we have already committed to and need some confidence.

Hi — this is an interesting project! I would recommend buying testing strips online or at a hardware store that test for pH, lead levels, bacteria levels, and something like nitrates and/or chlorine. There seem to be many testing strips available on amazon.

Unfortunately, PPCPs could encompass so many different types of contaminants that one may find to be unsafe (including different pharmaceutical compounds etc) that it is very unlikely you will be able to test for many of them with a product you would be able to buy as a consumer. (In fact, after some research it seems like many compounds you may be looking for are difficult to test in a laboratory setting.) I wonder if you would find it alright to test for less.

Also, when we are thinking about the safety of reclaimed water, you may find it useful to reframe the question slightly. Are the compounds found in common pharmaceutical products harmful when there are trace amounts of the skin or only when they are orally consumed? How much time do you expect the average student to be in physical contact with the grass that the reclaimed water will be used on. There are many common fertilizers which are deemed safe for use about children, but would not be safe if eaten.

I hope this helps!

Hi Kelly,
This is a cool experiment! Could you tell us more about your experimental setup? Are you pouring these 3 water types over pieces of sod and checking the quality of the runoff you get? I may be way off with that guess, so details of your experiment will help us give you the best feedback.

I like Clur_v's idea of broadening what you're looking for in the water to harmful compounds other than pathogens.
If your question is specifically pathogen based, I might narrow it to bacteria, as that will be the most straight forward to test.
I love the idea of test strips -had no idea those existed!

If your samples test positive for bacteria, a good next step is plating a little of your runoff samples on sterile agar plates and leaving them to grow overnight. This would allow you to compare the bacteria from each sample, giving you more detailed data for your project.