2. Water Testing

Turbidity

●     Turbidity measures how clear water is.

●     Water that has a high turbidity level is murky/turbid and difficult to see through, because it contains a large amount of suspended particles such as clay, silt, dead plant matter and even microscopic organisms.

●     Turbidity should not be confused with colour, since dark-coloured water can still be clear and not murky.

●     High turbidity levels may be caused by soil erosion, runoff after heavy rain, growth of algae or disturbance of sediment by boats or aquatic animals.

●     The unit of measurement for tubidity is the Jackson Turbidity Unit (JTU).

●     Water that has a turbidity level of around 20–40 JTU is likely to support aquatic life the best.

Steps to Measure Turbidity

1. Ensure that the white plastic cylindrical container has a Secchi disc sticker pasted on its inside bottom.

2. Fill the container with water taken from the water body (A).

3. Compare the appearance of the Secchi disc in the container with the turbidity chart (B) to determine the turbidity level of the water sample (C).

4. Record the turbidity data in JTU.

Dissolved Oxygen

●     Dissolved oxygen is the amount of oxygen that has dissolved into a given amount of water.

●     The unit of measurement for dissolved oxygen is parts per million (ppm) or milligrams per litre (mg/l).

●     For water to support aquatic animals, it must contain a certain amount of dissolved oxygen, since aquatic animals require oxygen to survive. Water that has a dissolved oxygen concentration of 7–9 ppm is able to support aquatic life the best. If dissolved oxygen concentration falls below 4 ppm, the survival of many fishes will be at risk.

What affects the amount of dissolved oxygen in water?

●     Temperature: cold water can hold more dissolved oxygen than warm water.

●     Time of Day: concentration of dissolved oxygen increases during the day as aquatic plants are able to photosynthesise, but falls gradually overnight.

●      Amount of Bacteria : High levels of bacteria or large amounts of rotting plants may cause the concentration of dissolved oxygen to decrease.

Steps to Measure Dissolved Oxygen

1. Fill the white plastic cylindrical container with water taken from the water body.

2. Immerse the small glass vial (A) into the water inside the container in order to fill it up (B).

3. Carefully take the vial out of the container and ensure that it remains completely full.

4. Drop 2 dissolved oxygen test tablets (C) into the vial.

5. Screw the cap on the vial and make sure that there are no air bubbles inside (D).

6. Shake the vial for 4 minutes until the tablets have completely dissolved (E).

7. Wait 5 more minutes for the colour to develop.

8. Compare the colour of the water sample in the vial with the dissolved oxygen chart (F) to determine its dissolved oxygen concentration (G).

9. Record the dissolved oxygen concentration data in parts per million (ppm).

pH Levels

●     pH is a scale to measure how acidic or alkaline/basic a particular liquid is. It ranges from 0 to 14.

○     A pH of 7 is considered neutral, meaning it is neither acidic nor basic, like pure water.

○     A pH less than 7 indicates acidity. The lower the number, the more acidic the substance. For example, lemon juice has a pH of around 2. You can identify acidity through its sour taste.

○     A pH greater than 7 indicates alkalinity (basicity). The higher the number, the more alkaline the substance. For example, soap or baking soda has a pH around 9.

How does pH levels affect aquatic life?

●     Most aquatic organisms thrive in water with a pH range of 6.5 to 8.5. If the pH is too low or too high, it can stress or even kill aquatic life.

●     The pH of water can affect the solubility and availability of nutrients and toxins. For instance, a low pH can increase the solubility of harmful metals, making them more toxic to aquatic life.

●     Maintaining a balanced pH is crucial for the overall health of the river ecosystem, including fish, plants, and microorganisms.

Steps to Measure pH

1. Fill the white plastic cylindrical container with water taken from the water body.

2. Immerse the plastic test tube into the water inside the container in order to fill it up to the 10ml line.

3. Carefully take the test tube out of the container.

4. Drop 1 pH test tablet into the test tube.

5. Screw the cap on the test tube.

6. Turn the test tube gently for a few minutes until the tablet has completely dissolved.

7. Wait for the colour to develop.

8. Compare the colour of the water sample in the test tube with the pH chart to determine its pH value.

9. Record the pH value.

Please note you will be measuring the level of dissolved oxygen in parts per million (ppm) 

Limitation of our water testing

We are only testing the water with the above parameters but the water quality could be affected by other parameters such as the amount of bacteria in the water.