Sampling and testing water for presence of fluoride

This is a water quality testing kit which tests for the presence of fluoride in any water sample. It contains a dark coloured plastic bottle labeled “Fluoride reagent” and a colour chart. With this kit you can test up to 30 samples of water for the presence of fluoride.
 
Please note: this kit only gives an indicative result and not an exact concentration of fluoride in the water sample.
 
Where to collect water sample:
Excess fluoride limits are typically found in groundwater, so look for a groundwater source of drinking water such as open wells, borewells or tubewells. Please view the “Sampling and Testing” video tutorial on www.thinkquest.com and http://schools.indiawaterportal.org/ for more information on these sources of water.
 
Procedure for collecting water sample:
If you are collecting the sample from a tap (supplied by a borewell) ensure that the water sample is collected before it is treated/purified.
  • Wash a plastic bottle at least 2-3 times with water. Each bottle should have a tight stopper or cap
  • Fill the bottle with the water sample to be analysed and cap it
  • Note the date and time of water collection and the location of water source (nearest postal address with pin code). Also note type of water source (e.g. open well/borewell/tubewell). It is important to note the exact postal address and pin code of the location from where the water sample has been collected, as it will help us correctly put up the results on an online map at the end of this water quality testing programme
  • Label the date and time of water collection and location details on the bottle
  • Bring the bottle to school for testing
Items required:
The water quality testing is best conducted in the Chemistry lab near a sink. Keep the following items ready before you start the test:
  • The water quality testing kit which has the fluoride reagent and colour chart
  • Water sample
  • One test-tube with a well-fitting rubber cork
  • One measuring cylinder of capacity 10ml. If there are only 25 or 50ml measuring cylinders in the lab, it is advisable to purchase a 10ml measuring cylinder for this test, since the larger ones will not be accurate enough
  • One test-tube holder
  • A notebook to record the details of the water sample and corresponding results
Testing procedure:
  • In a notebook make a note of the date and time of each water sample collection as well as the location (postal address with pin code) and type of water source
  • Wash the measuring cylinder, test-tube and cork
  • Rinse the measuring cylinder, test-tube and cork with a little bit of the water sample to be tested
  • Shake the measuring cylinder, test-tube and cork to remove as much of the residual water as possible
  • Measure 4 ml of the water sample using the measuring cylinder. Keep the measuring cylinder at eye level to avoid parallax error
  • Transfer this 4ml into the test-tube
  • Put 15 drops of the fluoride reagent into the test-tube that has the water sample
  • Cork the test-tube and shake it gently so that the reagent mixes uniformly with the water sample
  • You will notice a change in the colour of the water sample
  • Compare the colour of the water sample with the colours on the chart in the kit
  • Against the water sample details (date/time/location) make a note of the level of fluoride mentioned against the closest colour on the chart
  • Empty the contents of the test-tube in the sink and wash the test-tube, cork and measuring cylinder thoroughly
  • You are now ready to test the next sample of water.
Take photographs or videos when you collect and test the water samples. Please refer to the full video “Sampling and Testing” for all the information on uploading and analysing your test results.