Science Buddies: "Ask an Expert"

What do scientists use to test lake water? Like finding the chemicals in a lake.

dear lavrick,

Regarding your question, scientists test for many substances in lake water, and the substances sometimes depend on what is surrounding or is near the lake. Scientists may test the acidity or basitity of the water (which can be tested by pH paper and pH indicators) and correlate that to disturbances in aquatic life in the lake. Also, scientists test for bacteria, protists (ex. ameoba), fungi, chlorine, and all different chemicals. As I said before, sometimes what is being checked in the water depends on what is around the lake. For example, if a coal mine is near the lake, scientists may check the acidity of the lake and the presence of coal and other chemicals that might be found in the lake. If you post back what you want to test for in lake water I might be able to tell you what is used to test for those substances and I might be able to help you develop a project. You can search through science buddies' science fair project search website(https://www.sciencebuddies.org/science- ... deas.shtml) Also, I wanted to remind you that working with lake water might be dangerous, so think about the danger involved before you plan out your project.

good luck,
scienceexpert123

Ok thanks for replying btw. From what i know I'm doing an Individual reserch project on the chemicals found in lake wazecha in Wisconsin. i was wondering how that would be tested.

dear lavrick,

When doing an experiment it is best to have one or very few variables, so with testing lake water I would suggest testing pH and chlorine content (it's probably the easiest to test and to find the supplies to test). To test for pH you need to use pH test paper, which is probably available at a pool supply store (or online http://www.amazon.com/PH-Test-Strips-80 ... 355&sr=8-1). Take samples of the water and put it into a test tube or some plastic apparatus that can store the water for testing. Using the paper is pretty easy, just dip the paper in and look at the color change and match it up to the scale on the cover of the box. (this is about pH http://en.wikipedia.org/wiki/PH). Chloride tests are pretty simular, but you are using chloride test strips, which is probably available from a pool supply store (or online http://www.amazon.com/LaMotte-Company-C ... 697&sr=8-2) The use of the strips is the same. You can analgize the pH and chlorine results to the destruction or preservation of the lake's aquatic life. I think this is a good and interesting project idea. If you have anymore questions or want to test for something else just post a message. Also, remember to be careful when handling lake water because it is probably very dirty. Also be careful to not fall into the lake.

good luck,
scienceexpert123

Hi lavrick,
Common contamination issues for lakes in your area include eutrophication (excessive growth of algae) caused by increasing concentrations of nutrients such as nitrate and phosphate and high salinity (usually sodium chloride) caused by dissolution and runoff of road salt, and pathogens (bacteria and viruses).

From existing online data, it appears that eutrophication is a problem for this lake:
http://prodoasjava.dnr.wi.gov/swims/pub ... ction=post

It would be a very good idea, before you begin, to gather all existing water quality analyses for the lake. Some can be located online:
http://prodoasjava.dnr.wi.gov/swims/pub ... eep%20Hole
If you have questions about those data, please ask. For info about additional available data, you should contact the Wisconsin Department of Natural Resources.

If you choose to study chloride, please keep in mind that chlorine and chloride are very different. Chlorine test kits are sensitive to hypochlorite ions (e.g. from bleach) which are highly reactive and very uncommon in natural surface waters. If you use chlorine test strips, you will likely find no detectable concentrations of chlorine, which would be a disappointing experiment. Chloride contamination is a more common concern for surface waters in areas like Wisconsin that use road salt. Chloride test kits are also available (search for "chloride test kit" or "sodium chloride test kit"). For natural waters, you would want a test kit that can detect concentrations in the range of approximately 10-300 mg/L, so test kits designed for pools probably won't have sufficient precision.

Hi Lavrick,

Science Expert 123 has given you some good suggestions for a project, and excellent safety precautions that you should pay attention to. I would also like to give you another idea for a really good project. Why don't you call your local water department and ask to speak with someone who works in the laboratory? You could probably find someone who could give you specific information on the concerns of the water quality of Lake Wazecha. Perhaps there is a problem with nitrogen or phosphorous contamination from farming run-off. Or, perhaps there is some industrial pollutant that is of concern. Someone who works at the water department would be able to give some ideas for a specific project, and that you give your project real practical significance. If you get any ideas, then write back and we'll give you suggestions for doing the analysis.

It can be scary making a telephone call to an unknown person to ask for information. However, do try to make the call yourself, if you can. Just call and explain to the person who answers the phone why you are calling, and ask if you can speak to someone who can give you the information. Hopefully, you will get some helpful information.

Another possibility to identify a specific project would be to check out the following website, which appears to be a group of volunteers that monitor the quality of lakes in Wisconsin. This group should be a great resource for additional ideas. I looked at one report and it looks like you will need to find out what oligotrophic means.

http://dnr.wi.gov/lakes/CLMN/reportsand ... older=CLMN

Good luck!

Donna Hardy

Hey for everyone thanks for the help its given me a bit of a foot hold on my project to get started. any other help will be apreciated also. But anyway thanks for the help again

Lavrick

Ok i have been studying the water in lakes and stuff like that what i need to learn is what type of things are used to test the water. The things i need to test for are Oxygen, Phosphates, Nitrates, and Salt levels in the water. so i was wondering what type of equipment would u recamend using, to get the best answer?

Hi Lavrick,
I combined your new topic with your old one so that experts can see the progress of your project and questions. Please add new questions related to this project in this same topic.

What is "best" will depend on the resources available to you, and I don't now what those resources are. For general information on how to analyze for those dissolved compounds, try a internet search for "oxygen analysis", "phosphate analysis", "nitrate analysis", and, if by salt you mean NaCl, "chloride analysis" and maybe "sodium analysis". The equipment required for these analyses can be costly, so you might want to seek the volunteer assistance of a water quality laboratory or some other organization that has direct access to equipment and expertise.

Good luck!
Chris

Lavrick wrote:Ok i have been studying the water in lakes and stuff like that what i need to learn is what type of things are used to test the water. The things i need to test for are Oxygen, Phosphates, Nitrates, and Salt levels in the water. so i was wondering what type of equipment would u recamend using, to get the best answer?

Lavrick-here are some links to the kinds of equipment commonly used:

http://www.forestry-suppliers.com/drill ... sp?cat=306
http://www.nitrate.com/nittest4.htm
http://www.amazon.com/Phosphate-Test-Ki ... B0006JDWGY


Some aquatic/fish supply stores have them, and there are rental agencies that you can rent meters from for a short time. Maybe if you explain it is for a school science project, the might be willing to lend you one for free or at a reduced rate.

If you do a web search for "environmental monitoring equipment", with your location, you should find local rental agencies.

Hope this gets you started!

Hi Lavrick,

Ellums has given you some good leads for the oxygen, phosphate, and nitrate analysis that you need to do. The salt concentration of the lake water can be measured using a conductivity meter. Here is a website that explains this type of measurement, and includes sources. http://www.electronics-manufacturers.co ... ity-meter/

The oxygen and conductivity monitors are very expensive, and you may not be able to include these measurements in your project unless you can borrow these meters, or take your sample to a local laboratory and use a regular laboratory meter. Do not worry if you can’t do all of the test measurements. If you can do just one or two of the tests, you will still have a complete project. Your background information would explain the environmental significance of the analytes that you are able to test for.

Here is an alternative method for nitrate analysis, using reagents that you make yourself:
http://lmer.marsci.uga.edu/datapage/nut ... trate.html This protocol does use cadmium, which is a toxic metal, so you would need to be careful if you used this protocol. And, here is a method for doing phosphate analysis:
http://science.csumb.edu/morocojo/chem_ ... eMeth.html
Both methods would give more accurate results if you had a spectrophotometer, but if necessary, you could make up standards at different concentrations, and compare the color intensity of your samples compared to the standards. Do you have access to a spectrophotometer at school?

If you use test kits, or if you make your own reagents for nitrate and phosphate analysis, you will need to explain the chemistry behind the test method. So do let us know which method you are using if you have any question about how the test methods work.

Have you thought about what type of container you will use to collect samples? You will need something that will hold enough volume for the testing, and that won’t add anything to the sample.

This is going to be a great project! Do let us know if you have any questions.


Donna Hardy