pH level
Collect a water sample. Dip a dry strip of litmus paper into the sample. Leave for a few minutes or until the litmus paper has changed colour. Compare the new colour of the litmus paper to the pH colour chart (any number below 7 is acidic, any number above is alkaline).
Nitrate level
Collect a water sample. Put about 2.5ml of the water into a test tube. Add an equal volume of nitrate-reducing reagent. Cover and shake the test tube until the contents are fully combined. Observe the colour of the mixture and compare it to the colour chart in the nitrate testing kit – from this you can approximate the nitrate concentration of the water sample in mg/L.
Turbidity
Secchi disk method (in a deeper part of the river)
Slowly lower the Secchi disk into the water and stop just when you can no longer see it. Record the depth (indicated by marks on the rope). Slowly raise the disk until it can just be seen again. Record the depth. Find the mean of these two depths to determine the Secchi depth.
Reagent test method
Collect a water sample. Compare the turbidity to a control solution of equal volume. Gradually add a turbidity reagent to the control sample until it is visually identical the water sample. A value can be determined in standard Jackson Turbidity Units.
Odor
Threshold Odour Test:
Collect a water sample. Add odorless water to the sample and stop when the sample itself is odorless. The last dilution before the sample becomes odorless determines the Threshold Odor Number (TON), which measures how much odor was present.
Annissa's IGCSE & IB Notes 